rvupgradestore.com Composet Products Fridge Defend
RV Life Magazine RV Park Reviews RV Trip Wizard
Glossary of RV terms.
RV Glossary

This glossary, originally compiled and edited by forum staffer Don Jordan and continually updated by forum staff, contains definitions of many terms common to the RVing community. Move the cursor over the alphabetical menu below and you'll see a drop-down list of subjects that you can click on.

AC, ac or a/c:

Abbreviation for air conditioner or air conditioning unit.

Also the abbreviation for alternating current, which applies to 110V power in your home or the 110V power hookup at a campground. This contrasts with DC, or direct current, which applies to the 12V systems on your RV or car.

Return to top of page


A UK term for the style of tow bar that attaches to the towed car and has a coupler that fits onto a ball at rear of a motorhome.

Return to top of page

AGM Battery:

See listing for Battery Types.

Return to top of page

Aires System:

A system of approximately 4,000 designated motorhome only short-stay locations throughout France. They are located next to rivers, on car parks, next to hotels, restaurants or Government buildings and vary between rough ground to purpose designed and landscaped areas. the idea is simple, to get you to spend money locally in shops, restaurants and other establishments.

There may be as few as 5 or as many as 200 parking slots at a single location. Most locations have water and sewer, and some will have electric hookup for a small charge. The electric hookup is likely to be only 4 amps.

Germany has a similar system, but they call them Stellplätze (stoppingplace). Italy also has a system they call Sostas.

Return to top of page

Amp Hour Rating:

Amp-Hour Ratings (AH) are generally calculated by the battery manufacturer in the following manner, commonly called the "20 Hour Rate" or "C/20"; A fully charged battery is discharged at a constant rate over a period of 20 hours until it reaches zero charge, defined as 10.5 volts. Amp hours are the product of the amps X time in hours, so if the battery produces 3 amps/hour for the entire 20 hour period, it is rated as a 60 AH battery (3 x 20 = 60). If it can produce 4 amps for the same period it is rated as a 80 AH battery, and so on.

Batteries can generally produce low amp rates more easily than high amp rates, so a 100 AH battery will produce 1 amp for 100 hours but will NOT generally produce 25 amps for 4 hours or 100 amps for 1 hour. At a 25 amp rate, the total capacity goes down substantially, probably on the order of 50% of the C/20 amp-hour capacity (see listing for Reserve Capacity). At a 100 amp rate, the capacity is better measured in minutes rather than hours.

Temperature affects battery capacity and the colder it gets, the less AH are available. The AH testing is done at 70 degrees but at 32 degrees the capacity is substantially reduced.

The Amp Hour rating is most meaningful when working with small electrical loads, e.g. some lights and the power needed to operate the numerous 12V circuit boards in a modern RV. For heavier loads, e.g. operating an inverter or running a pump for extended periods, the RC (Reserve Capacity) rating is more meaningful. (See listing for Reserve Capacity).

Return to top of page

Air Bag:

An integral part of the suspension of a motorhome. On older gas motorhome chassis, an air bag might be used inside each of the two front supension coils to provide additional capacity to the front suspension. On a diesel motorhome, the chassis may rely on several air bags to provide the main suspension.

Return to top of page


CB: (View photo)
Generally an externally mounted unit that picks up the CB radio signals and conducts them to the CB transceiver inside the RV via co-axial cable. In the case of hand held CBs, the antenna is mounted directly on the transceiver.

Satellite antennas are frequently referred to as dish antennas. There are several types used in RVing. Roof mounted units may be manually or automatically aimed for maximum signal strength from the satellite. Some automatic roof mounted units are able to track the satellite signal while the vehicle is in motion and can provide TV or music.

Portable satellite antennas are free standing units that connect to the RV via coaxial cable in lengths of up to 100 feet. There are advantages to this type dish: 1) it can be placed almost anywhere within the radius of the coaxial cable length. This allows a signal to be received in many locations where the roof mounted units are blocked by trees or other obstructions; 2) No holes are needed through the RV roof. In general they are more difficult to aim than the roof mounted units (see Marriage Saver).

The dish is connected to the satellite receiver in the RV via coaxial cable for the TV signal and via a multi-conductor wire cable for directional control of the dish in the case of automatic units.

Television: (View photo)
Many RVs come with roof-mounted television antennas designed to pick up standard broadcast band TV stations. There are both manually controlled and electrically controlled models. The roof-mounted antenna is usually connected via coaxial cable to an amplifier unit inside the RV to improve the signal strength in outlying areas. Connection from the amplifier to the TV set is also via coaxial cable.

Manually controlled units are usually raised via a crank mechanism on the ceiling of the RV and then oriented via a wheel mechanism. Electrically controlled units have a control panel mounted inside the RV in a place where the TV screen is visible while the antenna is oriented. There are controls for raising and lowering the antenna and for rotating it in both directions.

Return to top of page

Arctic Package:

Specialized equipment added to an RV that includes extra insulation, double glazed windows, and heating pads for holding tanks for winter usage.

Return to top of page


ATVs (All Terrain Vehicles) are small 3 or 4 wheel vehicles used by many RV owners for off road exploration. The 3 wheel versions are no longer in production due to safety considerations (they are far more likely to tip or roll over than the 4 wheel versions). ATVs are rugged and able to handle rough and often steep back country dirt roads, sand dunes, etc. Either 2-cycle or 4-cycle engines that are quite powerful for the size and weight of the vehicle may power them. ATV’s are ridden astride in a manner similar to a motorcycle. A second person may also be accommodated in tandem, riding behind the driver.

ATVs may be carried in a Toy Hauler (see listing in Recreational Vehicle Types), on a small trailer towed by the RV, or in the bed of a pickup truck that is the towing vehicle for a travel trailer.

Return to top of page

Auxiliary Brakes:

Engine Brakes:
Engine brakes, also known as Jake Brakes, are units designed to help the towing vehicle to stop or slow down without excessive use of the vehicle's service brakes. There are units available for both gasoline and diesel engines with the latter being more common. Either type works by modifying the valve timing in some manner while cutting the fuel supply to the engine. They then use the engine as a large air compressor, sucking in air on the intake stroke and then closing the valves so that on the compression stroke the air is compressed. At, or near, the top of the compression stroke the valves are opened allowing the compressed air to escape. The cycle continues as long as the engine brake control is actuated. When the control is turned to the off position, the valve timing is restored to normal and fuel is again supplied to the engine. This type unit is normally quite noisy and many cities have banned their use.

Exhaust Brakes:
Diesel engines have poor compression slowing due to the fact that the air inlet to the engine is wide open at all times - there is no butterfly valve as is found in gasoline engines. To get around this problem several manufacturers supply diesel exhaust brakes. They consist of a heavy-duty butterfly valve mounted immediately following the turbo charger in the exhaust system. An electric solenoid or a pneumatic cylinder actuates the butterfly valve. It is normally in a position so that it is parallel to the flow of exhaust gases and presents little restriction to the exhaust flow. When actuated, the butterfly is closed to almost completely block the path of the exhaust gases. This forces the engine to act like a large air compressor and provides substantial braking action.

Towed Vehicle:
Many states and Canadian Provinces now require auxiliary brakes on vehicles towed behind an RV. There are a number of types of auxiliary brakes available. Some require modification of the vehicle while others do not.

There are two basic types of auxiliary brake for towed vehicles: passive and active.

The passive types are various variations on the surge brake. When the towing vehicle slows and/or applies its brakes the towed vehicle tries to continue on its path. This causes the weight of the towed vehicle to push on some type of mechanism that then mechanically or electrically applies the towed vehicle's brakes.

Active auxiliary brakes are power brakes of one type of another. There are three basic power sources for this type brake: electric, air, or vacuum. In this category some units are permanently mounted to the towed vehicle, usually under the hood, while others are portable and must be put in place each time they are to be used.

Return to top of page


A retractable cover, usually made of fabric, with metal arms that allow the awning to be extended or retracted from the exterior walls of an RV. The main prupose of an awning is to provide sun shade or, in some cases, to provide cover from rain.

An awning may be extended and retracted manually or electrically, depending on model. Some electrically operated awnings have the additional feature of automatically retracting in the presence of high wind. Awnings may cover one or more windows &/or the door of an RV.

Return to top of page

Axle Ratio:

The number of rotations of the drive shaft (on rear-wheel-drive vehicles) or output shaft (on front-wheel-drive vehicles) required to rotate the drive wheels one full turn. e.g. on a vehicle with an axle ratio of 4.1:1, the driveshaft would have to rotate 4.1 times in order to rotate the drive wheels once.

Higher axle ratios result in added torque for increased power for acceleration desirable when towing a trailer.

Return to top of page

Back-in Site:

A campsite that requires an RV to be reversed into (or backed into). See also listing for Pull-Through Site.

Return to top of page

Backup Monitor:

A camera (View photo)in the back of a motorhome, with the monitor positioned somewhere within easy view of the driver (View photo), to aid in backing up the motorhome. It is also used while driving to see the traffic behind and to keep an eye on the towed vehicle.

Return to top of page

Ball Mount:

The part of the hitch system that supports the hitch ball and connects it to the trailer coupler. Ball mounts are available in load carrying and weight distributing configurations.

Return to top of page

Basement Storage:

This is an alternate term for storage bays (see listing) and refers to storage areas beneath the floor of the RV accessible from the outside.

Return to top of page

Battery Capacity:

The capacity of a battery, specified in amp hours or ampere hours, usually abbreviated to AH, denotes the product of the current that can be delivered and time. So, a 100AH capacity suggests that 1 amp could be delivered for 100 hours, or 10 amps could be delivered for 10 hours. However, it should be noted that a battery cannot be totally discharged, nor is it desirable to repeatedly discharge a battery more than 50%. So it's appropriate to divide these numbers by 2. Furthermore, this method of specifying a battery is mainly appropriate for deep cycle batteries used as house or coach batteries.

Return to top of page

Battery/Battery Bank:

The battery or battery bank - more than one battery connected in a parallel, series, or series/parallel configuration (see Battery Connection listing) is the source of DC power for use inside the RV or for powering the various DC requirements of the RV's engine and chassis in the case of motorhomes. The chassis and the coach have separate battery systems. The converter (see listing) charges the batteries when the RV is connected to shore power or when the RV's genset (see listing) is in operation. Another method of charging is via the motorhome's engine alternator while driving.

Batteries come in two different flavors, starting and deep cycle. The starting battery, the battery of a tow vehicle or the chassis battery of a motor home, is designed to give a sudden burst of power to turn over an engine. It has a large number of thin plates to provide a large surface area to provide that sudden burst of amperage. If it has to endure a steady large amperage drain those thin plates are quickly damaged. If it has to be constantly recycled from heavy discharges to full charge it deteriorates rapidly.

A deep cycle battery, on the other hand, is designed for steady low to medium amperage discharge with occasional bursts of high amperage requirements (as for running a microwave oven via an inverter (see listing)). It has fewer, thicker plates than a starting battery in order to handle this type of cycling day after day. This is the type of battery that should be used as a house battery in a motor home or the trailer battery in a trailer.

Some batteries are sold for marine applications as start/deep cycle batteries. For marine use in small boats, these batteries are designed to turn over engines and then run the relatively low draw of bait tanks, anchor lights, and down rigger winches. They are NOT suitable for RV use being neither fish nor fowl.

Return to top of page

Battery Connections:

There are four basic methods of connecting batteries to each other or to the load (those pieces of equipment being powered by the battery or battery bank).

Single Battery:
As the name implies, this is a single battery (normally rated at 12.6 volts) that supplies all of the power to the system. In virtually all modern systems the negative terminal of the battery is connected to the vehicle's chassis and the positive terminal is the hot lead to which the equipment is connected through fuses, circuit breakers, etc. This system is usually the least costly but supplies the lowest current when compared to other methods of connection.

Series Connection:
In this set-up two or more batteries are connected in a daisy chain with the positive of one battery connected to the negative of the next battery. The negative terminal of the first battery is connected to chassis ground while the positive terminal of the second battery is the hot lead for the battery bank. In 12-volt systems the two batteries in a series connection must be 6-volt batteries - the sum of the two voltages being equal to 12 volts. This system can usually provide more power than a single 12-volt battery due to the more rugged construction and thicker, heavier plates of 6-volt batteries. The maximum current available is limited to the current available from a single battery but the power is double that available from the single battery (power = voltage x current) and since the deep cycle (see listing) 6-volt batteries used in RV's have higher amp-hour ratings than similarly sized 12-volt batteries, more over-all power is available.

Parallel Connection:
In a parallel connection of two or more batteries, all of the positive terminals are tied together via jumper cables and all of the negative terminals are similarly connected together. All of the negative connections are wired to chassis ground while all of the positive connections function as the positive terminal of the battery bank. In RVs that require a 12-volt power source for internal equipment, all of the batteries in a parallel battery bank must be 12-volt batteries of the same size and rating. In this setup, the total power available is equal to the number of batteries in the bank times the power rating of a single battery as used in the bank.

Series-Parallel Connection:
As the name implies, this system is a combination of series and parallel battery connections. In a 12-volt system two 6-volt batteries are connected in series (see listing above) to provide 12-volts. Then two or more of these series connected battery banks are connected in parallel (see listing above) to multiply the power available. This system provides the greatest power in the space available when 6-volt golf cart batteries (see listing) are used as the individual batteries.

Return to top of page

Battery Minder:

A small battery charger intended to maintain a battery in a charged state, usually while in storage.

Return to top of page

Battery Tender:

See listing for Battery Minder.

Return to top of page

Battery Types:

Lead Acid: (View photo):
Wet lead-acid (or flooded lead-acid) batteries are the most commonly used batteries in RVing. They are available in vented types (most common), where water can be added, and also in sealed types, where water cannot be added. They are almost always the least costly to purchase.

Absorbed Glass Mat or AGM:
This type battery utilizes a fiberglass mat saturated with sulfuric acid between the individual plates of the battery. AGM batteries are also sometimes called starved electrolyte or dry, because the fiberglass mat is only 95% saturated with sulfuric acid and there is no excess liquid. They are cleaner than lead-acid batteries, can take a fair amount of abuse, are non-spilling even when broken, and are far superior in most cases. AGM batteries are totally maintenance free, do not gas, and can be mounted in any plane. Their cycle duration (maximum number of charge-discharge cycles in the battery's life) is 6 to 10 times that of a flooded cell. They can deliver up to 30% more current than an equivalently sized flooded cell battery and will recharge to about 90% of their rated capacity as compared to 75% for the flooded cell. The major disadvantage of AGM batteries when compared with flooded lead-acid batteries is that they cost about 2 to 3 times as much. In situations where fumes, leakage or battery orientation are not a problem, the more economical flooded lead-acid is probably a better choice.

Gel Cell:
This type battery is frequently selected in applications where batteries cannot be vented or cannot be mounted in an upright position. They are cleaner in the sense that they do not vent gases like flooded lead-acid batteries.

Gel Cell batteries are more sensitive to charge voltage and cannot typically be charged with an automotive type battery charger since they cannot vent except in emergencies (which may cause irreversible damage).

Gel Cells are much more sensitive to higher temperatures and cannot tolerate being discharged for long periods of time compared to a flooded lead-acid battery. Consequently, the charge on gel cells must be regulated properly. It is important to follow the manufacturer's recommended regulation set points. Gel Cell batteries may require an external battery temperature compensated regulator.

Due to the charging sensitivity issues this type battery is probably not a good choice for use in the average RV.

Return to top of page

Batwing antenna:

A manually deployed antenna for receiving off-the-air TV channels. See the listing under antenna for more information.

Return to top of page


The National Biodiesel Board defines biodiesel as a domestic, renewable fuel for diesel engines derived from natural oils like soybean oil, and which meets the specifications of ASTM D 6751. It can be used in any concentration with petroleum based diesel fuel in existing diesel engines with little or no modification. The NBB goes on to explain that biodiesel is not the same thing as raw vegetable oil; It is produced by a chemical process which removes the glycerin from the oil.

Return to top of page

Black Water Tank:

The tank in which black water waste can be held until an approved dump station is available. Black water is the waste from the toilet.

Return to top of page


Bureau of Land Management. See the entry for Campgrounds for an explanation of BLM campgrounds.

Return to top of page

Blue Boy: (View photo):

This term refers to a portable waste holding tank that frequently has wheels on one end to facilitate moving or towing it to the waste disposal site. These plastic tanks often come in a bright shade of blue, hence the name.

Return to top of page


Also known as dry camping, boondocking refers to camping without any hook-ups, namely camping without hooking up to any electric, sewer or water facilities. You can still have electric power from your RV batteries, solar panels, wind turbine or AC power from a generator and water from your freshwater holding tank.

Return to top of page

Brake Controller:

A device installed in a tow vehicle to supply power to, and control the operation of, the electric brakes on an attached trailer. Several types are available and they differ in internal design and the number of axles (brakes) they can operate, but they all fall into two main groups, Proportional or Timed.

The most common Proportional brake controller detects how quickly the tow vehicle is stopping and applies a proportional amount of braking power to the trailer. There are also a few brands of controllers that directly measure the hydraulic pressure in the tow vehicle brakes and use that to control the power sent to the trailer brakes, but these require physical modification of the tow vehicle's hydraulic brake system and are not popular.

With a Timed brake controller, activation of the tow vehicle brakes sends a small fixed amount of power to the trailer brakes, and this amount is increased over a short time until full power is applied. This is less effective than porportional braking, but simpler to install and set up for use.

Return to top of page

Breakaway System:

A system designed to automatically lock the trailer or towed vehicle brakes in the event of a hitch failure and the trailer or towed vehicle breaks away from the tow vehicle.

There are different systems based on the type of brakes on the trailer or towed vehicle. In general, a fairly lightweight breakaway cable is attached between the towing vehicle and an actuator on the front of the trailer or towed vehicle. If the trailer's brakes are electrically operated the actuator is a switch that applies the full battery power from the trailer's battery to the electric brakes on the trailer.

If the braking system on the towed vehicle is air pressure operated the actuator is a switch that is normally held in the off position by an insulated plastic rod that is pulled out by the breakaway cable. This completes an electrical circuit that operates a solenoid air valve to release air pressure that has been stored in a special tank on the towed vehicle. The air pressure then is applied to the braking system on the towed vehicle and locks the brakes.

Return to top of page

BTU (British Thermal Unit):

A BTU is defined as the amount of heat required to raise the temperature of one pound of liquid water by one degree from 60 to 61 degrees Fahrenheit at a constant pressure of one atmosphere. It is commonly used in the RV world to compare the heat outputs of appliances such as water heaters, gas grills, air conditioners and such. For practical purposes, differences of less than 1000 BTUs are not very significant except in very small appliances.

Return to top of page


Bubble is another term with multiple meanings to the RVing world. It can refer to the degree of leveling of the RV. Example: my RV is off level by a half a bubble (referring to a bubble leveler tool)

Another sense of bubble refers to a form of delamination (see listing) of the RV's wall or roof construction.

Return to top of page

Bumper Pull:

See Bumper Pull Trailer.

Return to top of page

Bumper Pull Trailer:

Bumper pull means simply that the hitch pivot point is at or behind the tow vehicle's rear bumper. It isn't a very precise term, but is widely used in the trailer business to distinguish this type of hitch mechanism from a fifthwheel or gooseneck hitch. Bumper pull is a broader term than "travel trailer", and and encompasses utility trailers car haulers, tow dollies, and boat trailers.

A bumper pull hitch may actually be in or on the bumper, or may be placed in a hitch receiver under the bumper.

One caveat - many travel trailers are too heavy to be pulled by a ball attached to a bumper, although they may generically be refrred to as a "bumper pull trailer". Be sure to check the tongue weight and GVWR (or actual weight) of the trailer against the bumper tow ratings.

Return to top of page

Bypass Valve:

The name for one or more valves that allow the fresh water supply to bypass the water heater during winterization. See winterizing.

Return to top of page


A generic term for a couple of different types of RV, including a motorhome and a truck camper. More recently, use of the term is limited to truck campers. See listing for RV Types.

The term camper is also used when referring to an RVer or someone who 'camps' in a tent.

Return to top of page

Camp Grounds:

Bureau of Land Management (BLM) Sites:
BLM Recreation areas are large tracts of land, primarily in the western US, managed by the Bureau of Land Management. Most have primitive camping areas where camping is allowed but without any developed sites and no hook-ups. You may essentially camp wherever you like. Interior roads are primitive, although most are passable by the majority of RVs. There is no charge for camping in these areas although a 14-day limit to each stay is imposed. After 14 days you may move to a different BLM area at least 25 miles distant for another 14 days. This can be continued for additional 14-day periods.

At some BLM sites, called Long Term Visitor Areas (LTVA), water and sewage disposal are available at a centrally located spot. However, it is strongly advised that you arrive at any BLM camping site with plenty of water and empty black water tank. As no electricity is available you should be prepared to generate your own power either with a genset, solar power, or a wind-turbine (see listings for the foregoing).

At LTVA sites season passes are available as are two week passes (as of Dec. 2002: $25 for two weeks or $125 for the season).

Corps of Engineers (COE) Camps:
A recreational facility built and operated by the Army Corps of Engineers as part of one of their construction projects, usually a dam (impoundment) or waterway (canals/locks). These parks are typically built to the COE's high engineering standards and feature well paved roads, large paved sites, water, good quality electric and water hook-ups and excellent maintenance of grounds and facilities. Sewer hook-ups may or may not be included. COE parks are a good choice for those who like sites on or near water and that have boat ramps. They are frequently wooded as well. Entrance fees are usually moderate, typically in the $14-$20 range depending on facilities and a 50% discount is available to those with a federal Golden Age or Golden Access Pass.

The COE also makes space for parks available to state and local governments, so a COE managed lake may also have state or local parks. These parks will be operated according to state/local standards and rules and should not be expected to be the same as COE-managed parks.

Condominium (Condo) Parks:
A condo Park is a property where each property owner has full title to his or her property. The community usually includes common property that is owned on a cooperative basis by all owners in the condominium. This common property might include parkland, parking areas, or even a golf course or lake. Maintenance is supplied to the community on a shared cost basis and is managed by a condominium committee. Officers for the committee are elected from the members of the condominium. Sometimes the committee, who in turn might hire the staff or assign the contracts to maintain the property, hires a professional administrator or maintenance manager.

The cost of maintenance is divided among the owners of the condominium and is billed as Condo Maintenance fees. These maintenance fees are in addition to local taxes.

Condos also make strict rules concerning what individual owners can do in, on or with their properties with regulations voted on by the owners. Usually any changes to the appearance of the property have to be approved by the membership.

Condominium properties are deeded real property that form a part of the owner's estate and can be sold by the owner or willed to his or her heirs.

Local Government Parks:
This is a generic term encompassing recreational areas operated by local governments at the county, town or city level. Facilities at these parks vary widely but they are usually quite low priced and sometimes even free. Size may vary from a few sites to hundreds. County fairgrounds often have RV facilities and are included in this category. Some localities use these parks to attract tourists to their area while others may intend them primarily for local residents. A few may be restricted to local residents and will have signs posted stating that, but this is fairly rare. County parks may be included in the campground directories such as Trailer Life and Woodalls, but often are not. It is often necessary to inquire locally to find these places. Local police are a good source, since they will know about the place and can also tell you authoritatively if you will be allowed to use it.

Membership Parks:
These parks sell memberships that allow the owner the use of their facilities as well as the use of the facilities of related parks. They are affiliated groups of individual parks and range from excellent to so-so in appearance and facilities. There is a buy-in fee for the membership and then annual "maintenance fees". Depending on how often the owner uses his membership, cost per day of camping can be relatively inexpensive.

Military Parks (FamCamps):
A Military Campground is a facility operated by a military base for use by Active and Retired military personnel possessing authorized identification. It is operated by the base recreational service organization, with non-appropriated funds. Some have hosts present, while others use a self-registration procedure. The campground may be on the base proper or at an off site location. Although facilities at each place vary they may include RV sites with hookups, RV dry camping areas, tent sites, and/or cabins. Most are on a first come, first served basis although some of the larger ones require reservations. Active duty members have priority over retired members. Some military campgrounds permit use by current or retired Federal civil service employees. Most campgrounds allow an active duty person to sponsor a camper to use the campground, such as a visiting family member.

National Parks:
Some National Parks have camping facilities for RVs as well as more rustic tent camping sites. Entry fees to the National Park generally do not cover camping fees as concessionaires operate camping facilities. Facilities and regulations are very similar to those of the US Forest Service Parks (see listing).

Municipal or City Parks:
See listing under Local Government Parks

Private (Commercial) Parks:
- Non-affiliated Parks:
These are privately owned parks not affiliated with any of the national groups such as Good Sam or KOA (see listings). They range from excellent, well-appointed camps to poorly maintained, run down places that appear to be left over from the early 1930's depression era. Many are listed in the various campground directories but care should be exercised in making your selection. Watch the ratings for amenities and cleanliness of the restrooms and showers. The better non-affiliated parks are fully comparable to the best of any other type park.

- Good Sam Parks:
Privately owned and operated campgrounds affiliated with the Good Sam Club for promotional purposes. Good Sam parks display the Good Sam logo and offer a 10% discount off the regular nightly rate to Good Sam members. While Good Sam claims the parks will be "the kind of place you want to stay", they do not state any particular standards for amenities, maintenance, etc. Still, they are mostly decent quality parks with water, electric and sewer hook-ups available and other amenities as well. Good Sam parks are listed and rated in the Trailer Life Campground Directory (see listing) and are highlighted with bold print and red dots on the maps. Prices vary according to location and amenities but in general run in the mid to upper range for the area.

- Kampgrounds of America (KOA):
These campgrounds are members of a group that have banded together for the advantage of advertising, accounting, purchasing power, etc. They are similar in nature to the Good Sam parks and offer 10% discount to those RVers who pay a $10 annual membership fee. They usually offer full hookup pull-through 50-amp sites with water and sewer as well as back-in sites and/or sites with water and electric but no sewer connection. Many also have boondocking (see listing) sites. Most KOA's also have small cabins available for nightly rental for those traveling without an RV.

In general, KOA prices are at the high end of camps in a given area.

Special District Parks (Water Districts, etc.):
Some local water districts, etc., operate camping facilities at their water storage lakes. These can vary from primitive sites with no hook-ups to full service RV parks with full hook-ups.

State Parks:
State Park camping is usually aimed at the tent, small trailer, etc., campers. They frequently have small sites; narrow twisting roads, and no hook-ups. Centrally located water hydrants and trash facilities give the camper at least minimal convenience. These parks generally are in heavily wooded areas and give the camper a back to nature camping experience. Many states have annual passes for camping in their parks.

US Forest Service Camps:
These are campgrounds located in a US National Forest and are under the control of the US Forest Service. They are typically built by the USFS but operated by concessionaires under contract to the USFS and subject to their rules and policies, which can vary a great deal from district to district. USFS parks are popular with families and nature lovers because of their deep forest locations that provide plenty of opportunity for a "back to nature" experience. USFS campgrounds are typically somewhat primitive in keeping with the nature of the surrounding forests. Access roads may be narrow, winding and unpaved, sites may be small and utility hook-ups may not be provided. However, this is not always the case, especially in the newer parks, and a campground guide should be checked for details on individual parks. Fees are typically low to moderate and Golden Age and Golden Access Passes are accepted for camping and entrance fees. However, Golden passes generally will not apply to concessionaire fees such as those for parking or fire wood.

NOTE: There are also independently owned and operated campgrounds in National Forests. These are operated under license from USFS but are not subject to federal campground policies, and do not accept Golden Age/Access Passes, etc. They will not display the USFS logo on their signs.

Return to top of page

Camp Host:

Also known as campground host. A workamper whose principal duty is to be a point of contact in the campground, answering questions. Most camp host positions are voluntary, i.e. they are unpaid except for a free campsite. See also the listing for workcampers.

Return to top of page


There are two senses of the word caravan as used in the RV world. The first is almost exclusively used in Great Britain and Europe. It is the word used there to describe house trailers, travel trailers, or fifth wheel trailers. The word is often abbreviated to van, although the latter has become a more generic term in the UK, used for various types of trailers and motorhomes.

The more common usage in the United States and Canada is to describe a group of RVs traveling together to a common destination. Large formally organized caravans may be spaced a few minutes apart with CB radios used for communication between members of the caravan. A "Wagon Master" (see listing) normally leads off with a Tail Gunner (see listing) as the last member of the caravan. The tail gunner watches for any caravan member that may have had trouble on the road and to assist in any way possible.

Return to top of page

Caravan Park:

A UK term for a campground.

Return to top of page

CCC (Cargo Carrying Capacity):

There are two legal definitions of CCC (Cargo Carrying Capacity), depending on the date of the certificate showing the value.

Prior to June 2, 2008, the RVIA standard weight label defined CCC as follows:

CCC or Cargo Carrying Capacity is equal to GVWR (see listing) minus UVW (see listing) plus the weight of fresh water in the tank and hot water heater, the weight of propane in the tank, and the SCWR (see listing). For the mathematically inclined:

CCC = GWVR - (UVW + SCWR + Propane + Water)

Beginning June 2, 2008, a new federal weight label superseded the RVIA label and redefined CCC as follows:

Cargo Carrying Capacity is the maximum allowable combined weight of all occupants and cargo carried in or on the vehicle. If the vehicle is a recreation vehicle trailer or motorhome and is equipped with a propane supply, the weight of full propane tanks must be included in the vehicle's unloaded vehicle weight. If the vehicle is a recreation vehicle trailer or motorhome and is equipped with an on-board potable water supply, the weight of such on-board water must be treated as cargo.

Thus CCC on the federal weight label of any vehicle produced after June 2, 2008 includes the weight of any water or passengers in or on the RV, and is equal to the GVWR minus the UVW and the weight of full tank(s) of propane. Mathematically:

CCC = GVWR - (UVW + Propane)

Return to top of page

Cargo Carrier:

Various open or closed storage/carrying containers that are typically roof or hitch mounted. For roof mounted versions see Storage Pod: Roof Mounted.

Return to top of page

Chassis Battery: (View photo)

The chassis battery or battery bank is the system dedicated to operation of the 12-volt (or in some cases 24-volt) DC requirements of the motorhome's engine and other drive-train components. Living space DC power should never be taken from the chassis battery bank.

Return to top of page

Check Valve:

A one-way valve, usually found attached to and behind the fresh water (aka city water) connection to an RV. The check valve prevents the contents of the fresh water tank from siphoning back into the city water supply.

Return to top of page

Class A/B/C Motorhome:

See listing for RV Types.

Return to top of page


A generic term referring to a class A motorhome or bus conversion.

Return to top of page


Corps Of Engineers, also known as Army Corps Of Engineers. See the entry for Campgrounds for an explanation of COE campgrounds.

Return to top of page

Cold Cranking Amps (See also Battery types):

An engine strating battery (or chassis battery) is required to deliver a high current for a short duration (while cranking the engine). So a key requirement for such a battery is the specified cold cranking amps.

Return to top of page


Combined Gross Vehicle Weight Rating, an alternate term for Gross Combined Weight Rating used in some RVing circles. See the entry for Gross Combined Weight Rating (GCWR).

Return to top of page

Composite (Composite Material):

The combination of two distinctly different matrials to form a new, stronger material. An example would be the combination of glass strands or glass mat with epoxy resin to form fiberglass. Unlike a metal alloy, the constituent materials in a composite retain their original physical and chemical properties.

Return to top of page

Converter (See also Inverter):

A converter is an electrical device for converting 120-volt AC power into 12-volt DC power. Most RVs with electrical hookups will have a converter, since many of the lights and some other accessories run on 12-volts DC. A converter may also function as a charger for the coach batteries.

Return to top of page


A hose that connects the air valves of inner and outer tires on duallies. The crossover functions to equalize the air pressure between the two tires. In the event of air loss in one tire, the crossover allows air from the other tire to equalize the pressures. A crossover also allows the two tires to be inflated at the same time.

Return to top of page

Curb Weight:

The weight of an RV with standard equipment and a full tank of fuel, but excluding cargo, driver and passengers.

Return to top of page

Deep Cycle Battery (See also Battery types):

Unlike a chassis battery, a battery used as the house battery or coach battery is required to provide low to medium current (amps) for an extended period of time before being recharged. An example of this use is when boondocking or not hooked to shore power. A battery specifically designed for this type of use is called a deep cycle battery. A key specification for deep cycle batteries is amp hours, or ampere hours, which denotes the capacity of the battery.

Return to top of page


Delamination is a form of failure of an RV's exterior (generally) surface. It may be in the form of blisters or bubbles (see listing) bulging out from the general surrounding area or in very severe cases may be in the form of sheets of the top surface breaking loose from the substrate with radiating cracks surrounding the main failure. Delamination is usually caused by water leaks and requires extensive and expensive repairs to prevent total failure of the wall or roof structure.

Return to top of page

Diesel Number 1, 2:

Diesel fuel is sold in two formulas, diesel #1 and diesel #2. The most common is diesel #2, but diesel #1 is sold in very cold climates where diesel #2 could gel.

Return to top of page Diesel Number 1

Diesel Puller:

The term for a motorhome with the diesel engine mounted in the front of the vehicle. Also known simply as a Puller.

Return to top of page

Diesel Pusher:

The term for a motorhome with the diesel engine mounted in the rear of the vehicle. Also known simply as a Pusher.

Return to top of page

Dinghy: (View photo)

This is the term for a vehicle that you are towing with your motorhome. It is also known as a Toad and provides local transportation while your motorhome is parked at a campground.

Return to top of page


See listing for Tow Dolly.

Return to top of page

Dry Camping:

Also known as boondocking, dry camping refers to camping without any hook-ups, namely camping without hooking up to any electric, sewer or water facilities. You can still have electric power from your RV batteries, generator, wind turbine generator or solar power and water from your freshwater holding tank.

Return to top of page

Dry Weight:

The weight of the RV without any fuel, empty freshwater and holding tanks, empty propane tank(s), and with no passengers or other goods.

Return to top of page

DSI (Direct Spark Ignition):

A means of lighting a gas burner using a spark instead of a pilot light. Found on most modern gas appliances as it conserves gas not used for a pilot light and also avoids the problem of the pilot light blowing out.

Return to top of page


A slang term applied to the dual wheels found on each side of the rear axle of pick-up trucks in particular but which is sometimes used with reference to the dual wheels on the drive axle of virtually all motorhomes.

Return to top of page

Dump Station:

Dump stations are facilities for dumping or emptying your black water and gray water holding tanks. This may be a campsite with a sewer hook-up, or a dump- site provided by an RV park or other camping site or specially designated dump sites at highway rest stops or at some fuel stops.

Return to top of page

Dump Valve:

A valve in the plumbing between a holding tank on an RV and the sewer connection, allowing the contents of the holding tank to be discharged (or dumped). There will usually be two such valves, one for the gray water tank and one for the black water tank. Occasionally, an RV may have three dump valves where, for example, there are two gray tanks.

Return to top of page


Ethanol-based fuel comprised of 85 percent fuel ethanol and 15 percent unleaded gasoline. This blend burns cleaner than gasoline, and results in reduced hydrocarbon exhaust emissions.

Return to top of page


ECC is the Electronic Climate Control used to automatically try to run both air conditioners from a 30A shore power hookup at the same time. It operates by staggering the startup of the two a/c units, and shedding one or the other when the current draw exceeds the 30A limit. It will also attempt a recovery when the current draw drops below that limit.

Return to top of page

EMS (Energy Management System):

EMS, or Energy Management System, senses the incoming electrical power (shore power) and manages which appliances and systemss are connected to the available power. EMS is typically installed in RVs that are wired for 50 amp shore power.

If the RV is connected to 50 amp shore power, all the appliances and systems can be powered, and the EMS does not impose any restrictions.

If the RV is connected to 30 amp shore power, the EMS automatically determines which appliances and systems (aka "loads") are powered. In practice, the EMS "sheds" loads according to a predefined priority.

The EMS is unable to detect the difference between 30 amp, 20 amp and 15 amp shore power. A switch is provided to manually let the system know when the RV is plugged into 'less than 30 amp' shore power.

Return to top of page

End Caps:

Usually associated with fiberglass RV construction, end caps are the front and rear sections of the roof that are visible from the front and rear respectively. The caps are typically fiberglassed to the main section of the roof to form a continuous roof structure.

Return to top of page Return to top of page

Engine Brake:

See listing for Auxiliary Brakes.

Return to top of page

Equalizing Hitch:

A hitch that utilizes spring bars that are placed under tension to distribute a portion of the trailer's hitch weight to the tow vehicle's front axle and the trailer's axles. This hitch is also known as a weight-distributing hitch

Return to top of page

ETG (Exhaust Temperature Gauge):

A gauge used to measure Exhaust Gas Temperature (EGT) and sometimes known as a Pyrometer. Exhaust Gas Temperature is one measure of internal combustion engine health and efficiency, and with diesel engines an ETG or Pyrometer can be used to determine if the engine is properly operating in its designed temperature range.

Return to top of page

Exhaust Brake:

See listing for Auxiliary Brakes.

Return to top of page

Fifth Wheel or Fiver:

See the listing for RV Types.

Return to top of page

Flooded Wet Cell:

See listing for Battery Types.

Return to top of page

FRED Chassis:

Acronym for front-engine diesel chassis. As the name suggests, the diesel engine on this chassis is located in the front, rather than the conventional rear location of a diesel engine on an RV chassis. The FRED can therefore be considered a diesel puller.

Return to top of page

Fresh Water Tank:

The tank in which fresh water can be stored for later use.

Return to top of page

Full Body Paint:

As the name implies, the entire outside (sides, roof, front and back) of an RV is painted. This contrasts with an exterior that has decals or stripes, with the areas between the decals and stripes left untouched, or an exterior that has neither paint nor decoration.

Return to top of page

Fuel Cells:

A frequently asked question is What is the difference between the generators currently used in RV's and fuel cells.

Good question. A number of benefits are claimed and are technically feasible, but some would require a paradigm shift in RV design and use.

Current gen-sets consist of an internal combustion engine (diesel, gas or LP) with an attached rotating electric power generator (AC generator or DC generator + inverter). In contrast, a fuel cell converts fuel directly into heat and electrical energy without a mechanical engine or generator, i.e. rotating parts. It looks and acts somewhat like a magic battery that is continuously recharged while you draw power from it. Because there are no moving parts and no engine exhaust, a fuel cell is silent, fumeless, non-polluting and produces no dangerous CO. It doesn't need oil changes, filters or tune-ups. On the surface, it would appear to be maintenance-free, but it is too early to be confident of that.

Electrical power:
The fuel cell produces DC electricity, which when properly regulated can directly power many devices as we do today from batteries and converters. It appears that a 10KW fuel cell is practical in a size similar to today's gen-sets, so with a suitable inverter (pure sine wave?) we could have both AC and DC power in large amounts. With 10KW available, today's 50A RVs could run for lengthy periods without shore power while still using electricity for water heaters and refrigeration. In fact, a total electric RV becomes quite feasible without giving up off-grid capability, so eventually it should be possible to eliminate propane appliances and piping from RVs. We might be using electric stoves and residential-style refrigerators!

Fuel cell designers say that 24 VDC or more could be drawn direct from the cell, which makes it possible to consider redesigning RV systems and appliances for direct current use, as an alternative to running everything off an inverter. Doubling today's DC voltage cuts the amperage in half, reducing wire sizes and energy loss. DC powered pumps can be more powerful, lights are brighter and heating devices up to 1000 watts become practical, so we may see expanded use of DC powered devices if the AC-only alternative does not pan out. But 24 VDC input to an inverter is also a big plus for power generation, so it seems to me that the AC powered, total electric RV is the most likely outcome.

What does it run on?
A fuel cell converts hydrogen and oxygen into water, producing DC electricity and heat. The oxygen can come from the air but hydrogen is a difficult and dangerous fuel to handle. Rather than using hydrogen from an external tank, it is preferred that the hydrogen be produced internal to the fuel cell using a device called a reformer that liberates hydrogen from some other fuel. For RVs and portable generators, the fuel of choice is propane (LP gas) because it is readily available, inexpensive and compatible with existing RV designs. There are, however, many alternatives and it is impossible to predict at this point which one(s) will be utilized in a commercially viable fuel cell generator. Methanol is another fuel with good potential and is politically attractive because it is produced from plants rather than oil wells. A gasoline reformer is also possible. In contrast, the fuel cells in the space shuttle are powered by exotic and expensive alkaline compounds that simply are not practical for mass market use.

Other possibilities:
A fuel cell generates heat and water as well as electricity, something referred to as co-generation. Since RVs need to produce heat for hot water and interior heating, systems like today's Aqua Hot seem likely. If the paradigm is altered such that an RV normally runs off its fuel cell as opposed to shore power, then heat is continuously available for hot water and personal comfort. Some water is also a waste product of the fuel cell and that could be potentially used as well. Volume is probably insufficient for normal consumption, but could be a boon for those camping far from any water supply.

There are a few commercially available fuel cell products in very limited use today, but price wise they are not yet competitive with other technologies. Ballard makes a 1200W (unregulated DC) fuel cell called the Nexa that is about the size of the small Honda suitcase generators except it requires an external fuel tank. Daimler Chrysler has a protoype car and there are some fuel cell buses running in a couple cities. Fuel cell powered electric cars seem likely, perhaps as soon as 2005 by some estimates. Long Island Power company is installing 45 GenSys fuel cells from PlugPower in 2003, about half in a power generation station and half in homes and businesses. There is already a McDonalds restaurant on Long Island that is partically powered by a fuel cell and 121 GenSys fuel cell powering sites across the nation. Net is we are close and can expect to see and hear a lot more about fuel cells in the next several years. However, you probably won't be able to buy your fuel-celled RV for a few years yet, so if you need new tires this year you may as well buy them now and hold off on that new rig!

Return to top of page

Fuel Station: (View photo)

A fuel dispenser normally located at the rear of one side on some toy haulers. It has a pump and a short hose so you can fill up gas cans, ATVs and other toys, and draws fuel from an onboard fuel tank which can also feed the generator.

Return to top of page


See the entry for Full Hookup.

Return to top of page

Full Hookup:

The ability to connect to all three of a campground's facilities: electric, water, and sewer. As some campgrounds may stretch the definition of "Full hookups", it is a good idea to check to be sure that there is no misunderstanding on the type of hookups available, particularly with reference to the electric power.

Return to top of page

Full-Timers, Full-Timing:

The term used for people who live in their RV full time, or at least the vast majority of their time.

Return to top of page


Borrowed from the boating industry, a galley is an on-board kitchen area.

Return to top of page

Gas Pusher

A motorhome powered by a gasoline engine installed in the rear of the chassis and providing drive power to the rear wheels. See also listings for Diesel Pusher and FRED (Front Engine Diesel).

Return to top of page


See listing for Gross Axle Weight.

Return to top of page


The outer layer of a fiberglass body material that results in a glossy finish. The gelcoat is applied in the mold during layup/fabrication of the fiberglass panels. The color seen on unpainted gelacoat finishes is in the gelcoat itself. Gelcoat will oxidize with prolonged exposure to the sun, and should be protected with an appropriate wax to prevent deterioration.

Return to top of page

Gel Cell Battery

See listing for Battery Types.

Return to top of page


An electrical device powered by gasoline or diesel fuel, and sometimes propane, for generating 120-volt AC power. Sometimes referred to as a "gen-set".

Return to top of page

Gen-Set or Genset: (View photo)

See Generator.

Return to top of page

GFI or GFCI: (View photo)

GFI (ground fault interrupter) or GFCI (ground fault circuit interrupter) is a device for disconnecting power to one or more 110V power receptacles in the event of a ground fault, such as a short between the hot wire and ground. Typically, a GFCI is incorporated into a duplex power receptacle, and is evident by two buttons; The two buttons might be alongside each other or one above the other.

A GFCI might also be protecting additional receptacles 'downstream' of the one containing the device.

In the event that a ground fault is detected, the device trips, and one of the buttons pops out. It can be reset by pressing the button. But, if it won't reset, the ground fault still exists. In this case, disconnect appliances and other things plugged into receptacles to find out which one is causing the problem.

The second button is a "test" button that allows you to test and verify that the GFCI decice is working correctly. GFCI devices should be tested periodically by pressing the "test" button to confirm that the device works (the other button should pop out). If the device does not function correctly, it should be replaced.

Return to top of page

Golf Cart Battery:

A type of lead-acid battery designed for heavy-duty use powering golf carts. They are generally rated at 6-volts and are always deep cycle batteries (see listing under Battery/Battery Bank). They supply high amperage and can be recharged many times without significant loss of ability to be recharged and are thus ideal for use in series or series-parallel (see listings) connections in RV's as house batteries (see listing).

Return to top of page


A type of trailer connection (hitch) that utilizes a ball mount which is placed over or slightly ahead of the rear axle of a pick-up or flat bed truck. It is similar in concept to a fifth wheel, but uses a ball coupler on the end of a vertical shaft to make the connection to the tow vehicle. It is typically found on farm equipment and horse trailers.

Return to top of page


A term used to describe the gradient, steepness, or slope of a hill. In the USA, this is normally expressed as a percentage (The higher the percentage, the steeper the hill), and is caclulated mathematically as:

Rise/(horizontal distance) * 100.

In the UK, this is normally stated as a ratio (e.g. 1 in 6), and calculated as:

Rise/(horizonal distance).

An alternative way of describing grade is as the angle of inclinination.

Return to top of page


The gram is the basic unit of weight or mass in the metric system (see listing). One pound equals 453.6 grams.

Return to top of page

Gray Water Tank:

The tank in which gray water waste can be held until an approved dump station (see listing) is available. Gray water is waste from the sinks and shower.

Return to top of page

Gross Axle Weight (GAW):

The weight an individual axle on a vehicle is actually carrying. See also the listing for GAWR.

Return to top of page

Gross Axle Weight Rating (GAWR):

GAWR is the maximum allowable weight on an individual axle.

Return to top of page

Gross Combined Weight Rating (GCWR):

The maximum allowed weight for a vehicle with all of its contents and passengers along with the weight of any towed vehicle and its contents. Known in some RVing circles as CGVWR. Also known as Train Weight in the UK.

Return to top of page

Gross Vehicle Weight Rating (GVWR):

GVWR is the maximum allowable weight of the vehicle. The GVWR is equal to or greater than the sum of the UVW (see listing) and the NCC (see listing) and consists of all of its contents including, but not limited to, all fluids (gasoline or diesel fuel, engine oil, LPG (Propane), water, holding tanks, etc.); all foods; all clothing, bedding, towels, etc.; all tools and spare parts, all toys (adult and children's) and all passengers (154 Lbs each) and pets.

Also known in the UK as Maximum Authorised Mass (MAM).

Return to top of page


A general term used to describe all aspects of vehicle behavior related to its directional control.

Return to top of page

Heat Strips:

Heat strips are simple heating elements in the air flow of roof a/c units. They look like a small version of the heating element in a small/portable fan heater. Roof a/c units containing a heat strip have a Heat position on the switch in addition to a Cool position.

Heat strips are OK to take some of the chill off in the morning, but nowhere near as effective as the furnace.

Return to top of page

Hitch Ball Size:

The hitch ball size depends on the vehicle or trailer pulled and is in the range from 1-7/8", 2", and 2-5/16".
  • 1-7/8" is for trailers up to 2000 pounds.
  • 2" is for up 3500 pounds with a 3/4" shank or 6,000 pounds with a 1" shank.
  • 2-5/16" is for 6000 pounds with a 1" shank and 6-10,000 pounds with a 1-1/4' shank depending on the stamped load rating.

Hitch Ratings:

  • CLASS 1: Considered a light duty hitch for towing no more than a 2000-pound trailer with a maximum tongue weight of no more than 200 pounds. Requires a 1 1/4" square hitch receiver and a 1 7/8" hitch ball.
  • Class 2: This is a medium duty hitch for tows of up to 3500 pounds and with a maximum tongue weight of 300 pounds. Requires a 1 1/4" square hitch receiver and a 2" hitch ball with a 3/4" shank.
  • Classes 3 and 4: Heavy duty hitches for weights up to 10,000 pounds when used with weight distributing spring bars or 6,000 pounds without such. Both Classes 3 and 4 use a 2" square hitch receiver. For 6000-pound loads a 2" or 2 5/16" hitch ball with a 1" shank is used.
  • Class 5: Extra heavy-duty hitches that are rated up to 14,000 pounds with weight distributing spring bars or 10,000 pounds without. Class 5 hitches use a 2 1/2" hitch receiver and require a 2 5/16" hitch ball with a 1 1/4" shank.
Return to top of page

Hitch Receiver:

The hitch receiver is an assembly that is firmly attached to the rear of the towing vehicle. It is frequently welded to the chassis of the RV. At the rear center of the assembly and extending a short distance beyond the body of the RV is the receiver itself. The receiver is usually a square cross-section steel tube into which the hitch drawbar is inserted and, depending on the hitch rating, ranges from 1 1/4" to 2 1/2" square. The drawbar is held in place by a strong hardened steel locking pin that goes through holes in both the receiver and the drawbar. The hitch receiver must be rated to tow at least as much weight as will ever be towed.

Return to top of page

Hitch Weight or Hitch Tongue Weight:

Hitch or tongue weight is the amount of a trailer's weight that rests on the tow vehicle's hitch. For travel trailers this weight should be 10% to 15% of the total weight of the trailer. For fifth wheels this weight should be 15% to 20% of the total weight of the trailer.

Return to top of page

Holding Tanks:

There are three different holding tanks on most RVs: fresh water tank, gray water tank and black water tank. (See the individual definitions)

Return to top of page

Honey Wagon:

A mobile service that, usually for a fee, will empty the waste holding tanks on an RV at a campsite. This is especially useful when camped in an area that has no hookups and where there is no local dump station.

Return to top of page


This term refers to the utility facilities supplied by a campground at each site. The major types of hookups are electrical, water and sewer. If all three of these hookups are available, it is termed full hookup. Hookups may also include telephone and cable TV in some campgrounds.

Return to top of page


A calculated value, horsepower is the amount of power needed to lift a 550-lb object a height of one foot in one second. Horsepower is often abbreviated to HP, and is calculated as:

HP = (Torque x Engine Speed)/5252

See also the listing for Torque.

Return to top of page


Another name for the RV's living space.

Return to top of page

House Battery:

This is the battery or group of batteries that supply 12-volt (or in some cases in top of the line coaches or bus conversions, 24 volts or more) DC power for lights, alarms, radios, etc. in the RV. The house battery bank also powers the inverter (see listing) if one is present. This type of battery or battery bank needs to be some type of deep cycle battery (see listing under Battery/Battery Bank).

Return to top of page


ICC is an abbreviation for Interstate Commerce Commission. In the case of a motorhome, ICC refers to the lights flashed to another driver to, for example, signal that it's safe to pull over after overtaking. The term is often seen as ICC Lights or ICC Switch.

Return to top of page

IFS/Independent Front Suspension:

A type of suspension system that allows each front wheel to move vertically independent of each other. This contrasts with a solid axle system in which movement of one front wheel affects the other front wheel.

Return to top of page

Inverter (See also Converter):

Inverters are electrical devices for converting 12-volt DC power into 120-volt AC power. There are two basic types available: modified square-wave and pure sine wave with the former being the most common and least costly. They are available in sizes ranging from as low as 30 watts up to 3500 watts or more.

Return to top of page


Leveling jacks:
Leveling jacks are units that are permanently attached to an RV for the purpose of providing a comfortable environment when the unit is parked on a non-level surface. There are a number of varieties available, some manually operated by a crank mechanism and some power operated. Leveling by jacks is pretty well limited to motor homes and top of the line towables. The owners manuals will identify the jacking system that can be used for leveling and provide the operating instructions.

Crank operated jacks:
Crank operated jacks are frequently found on the tongue of travel trailers, pop-up trailers, etc. and are used to provide fore and aft leveling. Other crank operated jacks would be found at the rear corners of this type of RV and provide lateral or side-to-side stability but are not used for leveling. Some fifth wheel trailers have crank operated jacks at the front and rear, usually at each corner, which are used for stabilizing the unit.

Power operated leveling jacks: (View photo)
Power operated leveling jacks may be found on larger travel trailers, fifth wheel trailers, some truck camper stabilizers and on various classes of motorhome and may be either electrically or hydraulically operated. Leveling jacks are found in two general systems: 3-point or 4-point. The 3-point systems have a single large jack near the front center of the coach with two lighter duty jacks, one on each side, near the rear of the coach. 4-point systems have a jack on each side near the front of the coach and another jack on each side near the rear. They may be either fully automatic or manually controlled. In either the fully automatic versions or the manually operated versions a sensor determines if the RV is not level and provides an indication which direction, side-to-side and/or front-to-back, needs to be raised or lowered. In automatic systems, a built-in computer takes the readings from the sensor and directs which jack(s) need to be raised or lowered with no further intervention from the user. In the case of manually operated powered jacks there is a control panel with levers or buttons that control each jack to raise or lower it as needed. There are different procedures recommended by different manufacturers to minimize the chance of torquing the coach body or chassis while leveling. At least one manufacturer recommends that for their 4-point jacks the user operate them in pairs: both jacks on one side or the other or both jacks on the front or rear. This minimizes the tendency to torque the RV chassis. Torquing the chassis can result in cracked windows and/or other body damage. Consult the manufacturer's operating guide for your specific brand of jack for suggested leveling procedures.

Stabilizer jacks:
Stabilizer jacks are used on fifth wheel trailers to hold up and stabilize the fifth wheel hitch when the trailer is set up for camping. They greatly improve the comfort level in the area of the coach that is over the gooseneck hitch, minimizing both lateral and vertical movement.

Truck Camper jacks:
These jacks are mounted at the four corners of a truck slide-in camper. They are mounted in such a way that they clear the outer edges of the bed of the truck and can extend to the ground without interference. They can be used to lift the slide-in camper so that the truck can be driven out from under it and then lower the camper unit to the ground for either storage or camping. If the slide-in unit is left in the bed of the truck while camping, the jacks can be extended to provide leveling and stability.

Return to top of page

Jake Brake:

An engine brake developed by a company called Jacobs. See listing for Auxiliary Brakes.

Return to top of page


A distance measurement equal to 1000 meters. One kilometer equals 0.62137 miles. The kilometer is the official distance measurement in Canada and Mexico and most other parts of the world. (See metric system listing).

Return to top of page

Kingpin: (View photo)

A device that connects a fifthwheel trailer to the towing vehicle.

Return to top of page


RV leveling can be accomplished in several ways. Site selection, looking for the most level available spot, is the beginning method. Once a reasonably level site is selected then further leveling of the RV is done by either using leveling jacks (found on many RV's) or by using blocks under the wheels. These may be lengths of 2x10 or 4x10 lumber or 10x10 patented interlocking plastic squares or by patented plastic or metal sloping ramps. In the case of putting dual wheels on blocks or ramps, care must be taken that both wheels of the dual wheel pair are supported, not just one wheel. This will prevent overloading and possibly damaging the single supported tire.

Return to top of page


The liter is the basic unit of volumetric measurement in the metric system (see listing). One U.S. gallon equals 3.785 liters or one liter equals 0.2642 U.S. gallon.

Return to top of page

LP Gas:

Liquefied Petroleum Gas (sometimes referred to as LPG, Propane Gas, or simply Propane). LP gas is used to fuel appliances in the RV, such as the stove, oven, water heater and sometimes the refrigerator. The tanks are mounted outside the RV with a fixed horizontal mount on motorhomes (View photo) and removable mount (View photo) on the A-frame of trailers. LPG tanks are usually rated in pounds or gallons.

Return to top of page


An electrical pump, usually 12 volts, that allows the content of black and gray tanks to be emptied into a remote sewer connection. One connection to the pump accepts a regular 3 inch RV sewer hose and the other accepts a 5/8 or 3/4 inch garden hose. The pump incorporates a cutting mechanism for grinding solid waste into particulates, allowing it to be expelled through the garden hose.

A macerator may be portable (i.e. hooked up each time it gets used), or permanently installed in the service bay of an RV.

Return to top of page

Marriage Saver:

These are small hand-held electronic units that are used by one person to aid in aiming satellite dishes for maximum signal strength. They are temporarily connected between the coaxial cable going to the RV and the dish antenna. They provide both a visual indication via a meter and an audible tone that varies in strength with the received satellite signal strength.

The dish is first set up so that the support mast is perpendicular and then the dish itself is rotated to the approximate azimuth (compass heading) and elevation to the satellite. Small changes are made in either or both azimuth and elevation to maximize the meter reading and the audible tone. After the signal is maximized, the Marriage Saver is removed from the coaxial cable and the connection is re-established directly.

Return to top of page

Maximum Authorised Mass:

UK term for Gross Vehicle Weight Rating. See listing for GVW.

Return to top of page

Meter (Distance):

The meter is the basic unit of measurement in the metric system (see listing). It is equal to 39.37 inches.

Return to top of page

Meter (Instrument):

Meters are the display units that show voltage, current, speed, etc. They may be analog (a dial with a moving pointer) or digital (LED, LCD, etc. alphanumeric displays).

Return to top of page

Metric System:

The metric system of measurement is used in most parts of the world outside of the US today. It is based on powers of 10 with the standard for length being the meter. The standard for weight is the gram and the standard for volume is the liter. Here is a table of the International System of Units prefixes for decimal multiples and submultiples of the basic units.

Factor Name Symbol
  • 10^24 yotta Y
  • 10^21 zetta Z
  • 10^18 exa E
  • 10^15 peta P
  • 10^12 tera T
  • 10^9 giga G
  • 10^6 mega M
  • 10^3 kilo k
  • 10^2 hecto h
  • 10^1 deka da
  • 10^-1 deci d
  • 10^-2 centi c
  • 10^-3 milli m
  • 10^-6 micro u (mu)
  • 10^-9 nano n
  • 10^-12 pico p
  • 10^-15 femto f
  • 10^-18 atto a
  • 10^-21 zepto z
  • 10^-24 yocto y

  • Examples:

  • 10^3 meters = 1 kilometer
  • 10^6 meters = 1 megameter
  • 10^3 grams = 1 kilogram
  • 10^-6 grams = 1 microgram
  • 10^-1 liters = 1 deciliter
  • 10^2 liters = 1 hectoliter

  • Return to top of page

    Mini Motorhome:

    An alternate term for a class C motorhome. See the listing for RV Types.

    Return to top of page

    Mobile Home:

    Not an RV, a mobile home is an alternative to a single family house, and intended for full time living. It is constructed on a trailer, allowing it to be moved to a semi-permanent location at a mobile home park. It may consist of two or more sections, each on their own trailer, and joined together at their destination. The combination of two units or sections joined in this manner is often referred to as a "double wide".

    Return to top of page

    Monocoque Chassis:

    A type of construction of chassis used on many buses and some motorhomes which uses frame members to surround the entire vehicle. This results in a very strong and rigid structure. See also the listing for semi-monocoque chassis.

    Return to top of page


    A generic term for a class A motorhome or a bus conversion.

    See listing for RV Types. Return to top of page


    See listing for RV Types. Return to top of page


    Manufacturer's Suggested Retail Price - the amount the manufacturer intended to have the retailer receive for the product. If the retailer sells the product for less than the MSRP, it is said to be selling at a "discount." MSRP excludes state and local taxes, and license fees.

    Return to top of page

    NCC (Net Carrying Capacity):

    NCC means the maximum weight of all occupants and goods including the driver, personal belongings, food, fresh water, LP Gas, tools, tongue weight of towed vehicle, dealer installed accessories, etc. that can be carried in the RV. NCC is equal to or less than GVWR (see listing) minus UVW (see listing). The term Cargo Carrying Capacity (see listing) is replacing NCC in new RVs.

    Return to top of page


    National Forest Service. See the entry for Campgrounds for an explanation of NFS campgrounds.

    Return to top of page


    National Parks Service. See the entry for Campgrounds for an explanation of NPS campgrounds.

    Return to top of page

    OCCC (Occupant & Cargo Carrying Capacity):

    As of June 2, 2008, the Federal DOT mandated a new weight label for motorhomes called the OCCC label. This replaces the previous RVIA CCC (Cargo Carrying Capacity) label and redefines how it is calcuated. OCCC is defined to be the difference between the motorhome GVWR and its unladen weight (ULW), but it requires that the ULW include a full tank of fuel and propane. Thus the OCCC gives the weight you have available for all passengers, gear, food, clothing, etc., plus any trailer tongue weight carried by the coach.

    The weights on the label must be for the particular motorhome, as configured for delivery to the dealer. Further, if the dealer installs additional accessories, he must provide an updated label. This assures the owner knows what he/she is actually getting in terms of carrying capacity.

    Per the FDOT website, the OCCC label has the following information:

    (a) The statement: "MOTOR HOME OCCUPANT AND CARGO CARRYING CAPACITY" in block letters.

    (b) The Vehicle Identification Number (VIN).

    (c) The statement "THE COMBINED WEIGHT OF OCCUPANTS AND CARGO SHOULD NEVER EXCEED: XXX kg or XXX lbs" in block letters with appropriate values included.

    (d) The statement "Safety belt equipped seating capacity: XXX" with the appropriate value included. This is the total number of safety belt equipped seating positions.

    (e) The statement: "CAUTION: A full load of water equals XXX kg or XXX lbs of cargo @ 1 kg/L (8.3 lb/gal) and the tongue weight of a towed trailer counts as cargo" with appropriate values included.

    NOTE: The OCCC label applies only to motorized RVs (motorhomes). There is also a revised definition of CCC for trailer RVs. See the Cargo Carrying Capacity glossary entry for more details.

    Return to top of page


    The abbreviation for "Original Equipment Manufacturer"

    Return to top of page


    The abbreviation for "Over The Air", a type of television signal or TV antenna.

    Return to top of page

    Park Model:

    These units are a special type of RV that is designed for permanent parking in an RV park or resort. They are generally shorter than traditional mobile homes but have essentially all of the amenities of a mobile home. They are not built for recreational travel.

    Return to top of page


    The term used for people who use their RV more than usual (more than just a few weekend trips a year), but who still use it less than full time.

    Return to top of page


    The amount of weight a vehicle can carry in its cargo area in addition to a driver and full fuel tank.

    Return to top of page

    Pin Weight:

    The weight that a fifth wheel trailer places on its kingpin, the device that connects it to the towing vehicle. The pin weight is typically 15-20% or more of the total weight of the fifth wheel trailer. See also the listing for Kingpin.

    Return to top of page


    In the UK, the term pitch is used to mean an individual campsite.

    Return to top of page

    Pop-Out (See also Slide-out):

    The term for a room or part of a room in an RV that pops out or slides out for additional living space.

    Return to top of page

    Popup or Pop-Up:

    This is another name for a folding camping trailer.

    Return to top of page


    A term used to define the fore and aft rocking or up and down motion in an RV while traveling. The regular spacing of the joints in concrete highways frequently causes Porpoising.

    Return to top of page

    Power to Weight Ratio:

    There are two common rule-of-thumb formulas for power to weight ratio, one based on horsepower and one on torque. These formulas will give a fairly good idea of how satisfactorily a vehicle will perform.

    • Horsepower to Weight: 1 HP for each 100 pounds of coach and towed vehicle. Example: 31,000 pound coach towing a 4000 pound vehicle = 35,000 pounds / 100 = 350 HP engine required.
    • Torque to Weight: 1 Ft-Lb of torque for each 33.3 pounds of coach and towed vehicle. Example: using the same coach and towed vehicle as above = 35,000 pounds / 33.3 = 1051 Ft-Lb of torque required.
    Using these formulas in evaluating a vehicle's suitability for your requirements should give good performance with respect to acceleration, passing ability, and hill climbing ability. Values less than 100 pounds per horsepower and/or 33.3 pounds per Ft-Lb of torque will give correspondingly better performance.

    Return to top of page

    Primitive Camping:

    See Boondocking listing.

    Return to top of page

    Propane Gas:

    See LP Gas listing.

    Return to top of page


    The slang term for a motorhome with a front-mounted diesel engine.

    Return to top of page

    Pull Through Site:

    A camping site that allows you to pull through while setting up and leaving the area, i.e. a site into which you do not have to back in or out.

    Return to top of page


    The slang term for a motorhome with a rear-mounted diesel engine.

    Return to top of page

    Quick Disconnect:

    Quick Disconnects are fittings for fluid, air, or LPG lines that allow rapid and easy leak-free connections to be made without the use of tools.

    Return to top of page

    Radio Types:

    Amplitude Modulation (AM):
    AM radio is the oldest type of voice transmission. It is more subject to static and other types of interference than FM transmissions. The information being broadcast is imposed on the carrier wave by varying the amplitude of the wave.
    Citizens Band (CB):
    CB radio is a system designed for personal two-way communications. CB transmitter/receivers may be either hand held or base stations. The FCC limits transmitting power of all CBs to 5 watts. Depending on the antenna (See listing in Antenna: CB:) the range for communication may be up to several miles. CB radios are amplitude modulated and are therefore prone to atmospheric interference that can severely restrict the useable range in stormy weather.
    Frequency Modulation (FM):
    FM radio eliminates atmospheric interference by limiting the amplitude of the waveform to a constant value. The voice, music or other form of information being transmitted is imposed on the carrier by varying the frequency.
    Family Radio Service (FRS):
    FRS radios operate in a portion of the General Mobile Radio Service (GMRS) frequency band and therefore require the user to obtain a Federal Communications Commission (FCC) license. Forms 605 and 159 can be obtained by mail from the FCC by calling 1-800-418-3676.

    FRS radios use FM and therefore are much quieter in use than CB radios. They are relatively small handheld units. Most have 14 channels and up to 38 privacy codes. Transmission range may be up to 2 miles in ideal conditions. They are ideal for personal communication while at shopping malls, rallies, while caravanning, etc., giving clear and undistorted sound.
    Ham Radio:
    Ham radio is a system of licensed communication for use by the general public. The user must pass tests that demonstrate his or her understanding of the regulations and, for some classes of license, an ability to send and receive Morse code.

    There are a number of different classes of license, each of which grants the holder access to specific modes of operation and/or frequency bands. Each advance in license class allows the holder all of the access and modes for the lower classes of license along with specific newer frequency band and/or transmitter power ratings. With the proper license a Ham may have very high-powered equipment that allows worldwide communications.

    Many members of the RV community are Hams and enjoy the use of their equipment from their RVs.
    Satellite Radios:
    A fairly recent development on the radio scene is satellite radio. This is a system where a number of channels are broadcast from an earth station to a satellite that rebroadcasts the signal to a wide footprint that basically covers the entire US. At the present time there are two satellite radio providers, each of whom charge a monthly fee to the user. Special antennas are required along with the special receiver. It may be a separate stand alone unit or a tuner that connects to the existing dash radio.

    At the present time most of the 100 or more channels available are commercial free. However the trend seems to be that more and more of the channels will have commercials on them.

    The big advantage of satellite radio is that one can tune in a channel on the west coast and then travel across the entire continent listening to that same channel. This, combined with the excellent static free reception, makes them a very attractive choice.

    Return to top of page

    Reserve Capacity:

    Reserve Capacity (RC) is measured by dischargeing the battery at a rate of 25 amps/hour until it reaches zero charge, defined as 10.5 volts. It is expressed in minutes, so an RC of 120 means the battery can produce 25 amps for 120 minutes (2 hours). While that could also be expressed as 50 Amp Hours (25 X 2 = 50), it is not the same as saying the battery has a 50 AH rating because the AH rating is measured differently (see listing for Amp Hour Rating). A battery with an RC of 120 would typically have an AH rating in the 80-100AH range.

    RC is most meaningful when the electrical load is fairly large, e.g. operating an inverter to power tv. A 25 amp discharge rate through an inverter will produce only 2.5 amps @ 120VAC (300 watts), so it is not a lot of power. A toaster or coffee maker, for example, would require much more.

    Batteries can produce low amp rates more easily than high amp rates, so a battery with an RC of 120 can produce 25 amps for two hours but CANNOT produce 100 amps for 1/2 hour. At the 100 amp rate the battery would likely last no more than 10-15 minutes.

    Return to top of page

    Recreational Vehicle Types: (View illustrated file)

    Bus conversions: (View photo)
    As the name suggests, a bus conversion is a highly customized coach on a bus chassis. In its prior life, the coach could well have been a commercial bus, and the interior completely remodeled. Alternatively, the bus conversion could be a new, specially manufactured shell mounted on a new bus chassis. Because they are highly customized, bus conversions are typically the most expensive type of RV.

    Floor plans are customized, as is the living and sleeping accommodations. Luxury is usually the operative word associated with the interior of bus conversions.

    They can often be seen on freeways with distinctively painted exteriors, and are frequently owned by celebrities to transport their entourage.

    Return to top of page
    Fifth wheel trailer: (View photo)
    A fifth wheel trailer, often abbreviated to 5th wheel or 5er, is a trailer designed to be towed by a pickup or medium duty truck equipped with a special hitch in the truck bed. The goose neck shape at the front easily distinguishes it. This elevated front section of the trailer often houses the master bedroom.

    Fifth wheels come equipped with all the conveniences of type A and C motorhomes. Depending on their length, they may also have two or more slide-out sections which, when extended, provide a large amount of interior space.

    A fifth wheel shares the advantage of a travel trailer in that it can be detached from the tow vehicle at your destination, thereby providing convenient transport for shopping, sight-seeing, etc. without the need to tow a car.

    Return to top of page
    Folding/tent trailers: (View photo)
    As the name suggests, the walls of this RV fold down to provide a lightweight, low-profile trailer that can be easily towed. When open, the trailer has some of the features of a tent, but the occupants are elevated off the ground.

    The folding camping trailer provides good utility at a very economical price. This makes it the ideal entry level RV. Amenities can include cooking and even shower facilities, depending on model.

    A lightweight unit with sides that collapse for towing and storage, the folding camping trailer combines the experience of open-air tent camping with sleeping comforts, basic conveniences and weather protection found in other RVs.

    Return to top of page
    Motorhome, Class A: (View photo)
    A self-contained motorized RV that looks something like a bus, often referred to as 'a coach'. Built on a special chassis, the Class A has all the comforts of home. Floor plans typically include separate living quarters, a fully equipped kitchen, dining area, one or more bedrooms, and one or more bathrooms. Newer models have optional "slide-outs", where one or more sections of exterior wall can be extended at the push of a switch to provide a much wider living area.

    Class A motorhomes vary in length from approximately 25 feet to 45 feet, and can be powered by a gas or diesel engine. They do not have a separate cab; the driver sits at the front of the coach.

    Return to top of page
    Motorhome, Class B (View photo)
    The Class B, or van conversion, looks like a large van, but is smaller than the Class C. Like the Class C, a van conversion typically has living, cooking, sleeping and bathroom accommodations.

    Some newer Class B units are essentially hybrids between a van and a Class C motorhome. They have wide bodies that flare out behind the driving compartment to provide more interior room.

    Return to top of page
    Motorhome, Class C (View photo)
    Generally smaller than the Class A, the Class C motorhome is built on a specially manufactured van chassis. Floor plans are similar to those of a Class A, but are more compact due to the smaller overall interior space. They typically include living quarters with an integrated kitchen, dining area, one or more bedrooms, and a bathroom.

    The forward cab, where the driver and passenger sit, easily identifies the Class C motorhome. The main body of the Class C usually projects over the top of the cab to house a bunk or storage space.

    Return to top of page
    Toy Hauler/Toy Hauler Trailer/Toy House Trailer : (View photo)
    These are RVs designed to provide both living quarters and space to haul ATV's, motorcycles, etc. inside the vehicle.

    Return to top of page
    Travel Trailer or Trailer: (View photo)
    A travel trailer is designed to be towed by a pickup truck equipped with a special hitch attached to the truck chassis or by a larger SUV with adequate towing equipment installed.

    Travel trailers come equipped with all the conveniences of Class A and C motorhomes. Depending on their length, they may also have one, two or three slide-out sections which, when extended, provide a large amount of interior space.

    A trailer has the advantage of being able to be detached from the tow vehicle at your destination, thereby allowing the tow vehicle to be used as transportation for shopping, sight-seeing, etc.

    Return to top of page
    Truck camper: (View photo)
    A truck camper is a specially designed unit carried in the bed of a pickup truck. This makes it ideal for remote, off-road locations.

    This versatile RV provides a significant amount of utility in a small space. Amenities can include kitchen, shower and toilet facilities, depending on model.

    The camper can be removed from the pickup truck using jacks mounted at each of the four corners, allowing the pickup truck to be used separately at the destination.

    Return to top of page

    Ride Height:

    The distance between the ground and a specified point on a vehicle with correctly inflated tires.

    Return to top of page


    Safety Chains or Cables:

    Safety chains or cables are attached to both the towed vehicle chassis (or trailer A-Frame) and to the towing vehicle while towing. They are intended to keep the towed vehicle or trailer attached to the tow vehicle in the event of a hitch failure, preventing complete separation from the tow vehicle.

    Return to top of page

    Satellite Internet:

    Satellite internet, as the name suggests, is a service for getting online via satellite. It usually involves having a special-purpose satellite dish installed on the roof of the RV or on a tripod in close proximity. It also requires a special modem and subscription to a service such as HughesNet. Satellite internet provides the RVer with a means of being online without the need for cellular service or a land line phone hookup. This is especially useful for RVers who prefer boondocking away from civilization, out of reach of WiFi or cellular phone service. However, the dish needs an unobstructed view of the sky in a southerly direction to be able to communicate with the satellite, so tree-shaded locations are undesirable.

    Return to top of page

    Semi-monocoque Chassis:

    A type of construction of motorhome chassis which uses frame members on the lower half of the vehicle to provide a very strong base for the rest of the coach. This contrasts with the cheaper frame rail type of construction. See also the listing for monocoque chassis.

    Return to top of page

    Service Brakes:

    The main (hydraulic or air) braking system on a vehicle operated by depressing the brake pedal. Service brakes operate independently from auxiliary brakes such as engine brakes, exhaust brakes, or parking brakes.

    Return to top of page

    Shore Power: (View photo)

    Electricity provided to the RV by an external source other than the RV batteries genset or inverter.

    There are several types of shore power connections available: 15 (or 20) amp, 30-amp, and 50-amp service. The 15 or 20 amp connection is the same as is found in a residence. The 30 amp and 50 amp connections are specialized connectors that prevent connecting the wrong type of circuit to the RV.

    When connected to a 15 or 20 amp shore power source, minimal power is available and only a few low power appliances can be used without overloading the circuit and blowing the shore power circuit breaker. Care must be taken not to use more than 1650 watts of power on a 15-amp circuit or 2200 watts on a 20-amp circuit breaker.

    With a 30-amp shore power supply up to 3300 watts of power can be used. This will allow the use of one air conditioner, a microwave oven, one or two TVs, etc. at the same time. Some RVs have specialized circuits that allow the use of two air conditioners at the same time by shedding other loads as the air conditioning load increases.

    So-called 50-amp circuits are 50 amps at 240 Volts. In reality, you are getting 100 amps of power (two 50 amp circuits - one on each leg of the 240 volt supply) at 120 volts A.C. enabling you to run more appliances simultaneously.

    Return to top of page

    Side by side hookups:

    Some campgrounds will put 2 sets of hookups on one pedestal and perhaps 2 water spigots on one riser; this is a side-by-side hookup. The adjacent RVs will pull into the sites in opposite directions. There are no particular disadvantages to this arrangement, unless you object having your door opposite the door of the adjacent RV and a common patio area.

    Return to top of page


    In the UK, the term site is used to refer to a campground. See listing for campgrounds.

    Return to top of page

    Sleeping Capacity Weight Rating (SCWR):

    Sleeping Capacity Weight Rating (SCWR) is another term recently adopted by RVIA. It is calculated by multiplying 154 pounds times the number of sleeping positions as defined by the RV manufacturer.

    Return to top of page

    Slide-In (See also Recreational Vehicle, Type, Truck Camper):

    The term for a type of camper that mounts on a truck bed, because this type of camper slides in to the truck bed.

    Return to top of page

    Slide-Out (See also Pop-out): (View photo)

    This is a room or area in your RV that slides out to make additional space for living. Slide-outs are generally power operated.

    Return to top of page

    Slide Topper:

    An awning that extends over a slideout and usually deployed automatically. It's main function is to keep leaves and debris from the top of the slideout which might otherwise damage seals or cause leaks when the slideout is retracted. See also the listing for Awning

    Return to top of page

    Slide tray: (View photo)

    A large storage tray mounted in external storage bays of some RVs. They are mounted on heavy support rails and have ball bearing rollers to allow the slide tray to be easily pulled out to gain access to items toward the rear of the bay. In the case of pass through bays (see Storage Bay) the slide tray can be extended towards either side of the RV.

    Return to top of page


    A class of RVer that migrates south during the winter months in search of warmer weather and to escape snow..

    Return to top of page

    Solar Power:

    A solar power controller is an electronic unit, usually mounted inside the RV, which receives the raw power from solar panels and limits the voltage and power passed on to the RVs 12-volt system. It prevents overcharging of the batteries while allowing the maximum usable power to be used.

    Return to top of page
    Solar Panel:
    Solar panels are units of various sizes and power ratings that are usually mounted on the roof of an RV where they are exposed to the sun's rays for as many hours each day as possible. They are most frequently made from an assembly of silicon solar cells mounted in a frame with a transparent cover to protect the cells from the elements. The cells are arranged in a series-parallel configuration to produce a voltage and current high enough to charge the RV's house battery bank and replace power used by the RV's various types of equipment during non-daylight or low daylight hours. They come in several power ratings ranging from 5 watts to 100 watts or more. They can be wired in parallel to provide as much charging power as desired and the user's pocket book can stand.

    Solar panels are units of various sizes and power ratings that are usually mounted on the roof of an RV where they are exposed to the sun's rays for as many hours each day as possible. They are most frequently made from an assembly of silicon solar cells mounted in a frame with a transparent cover to protect the cells from the elements. The cells are arranged in a series-parallel configuration to produce a voltage and current high enough to charge the RV's house battery bank and replace power used by the RV's various types of equipment during non-daylight or low daylight hours. They come in several power ratings ranging from 5 watts to 100 watts or more. They can be wired in parallel to provide as much charging power as desired and the user's pocket book can stand.

    Return to top of page


    An Italian name that refers to designated short-stay RV sites. See Aires System for information on a similar system in France.

    Return to top of page


    See Stabilizer Jacks under the listing for Jacks.

    Return to top of page


    A German name for stopping place, and refers to designated short-stay RV sites. See Aires System for more information on a similar system in France.

    Return to top of page

    Sticker Price:

    See listing for MSRP. Also known as "window sticker price", the name comes from the fact that a manufacturer lists the base price, the price of all options, and the resulting MSRP on a sticker or label, usually stuck on the window of a vehicle. In the case of motorhomes, the sticker is often found loose on a counter rather than actually stuck to a window.

    Return to top of page

    Storage Bay:

    (View photo): These are externally accessible storage areas that are usually located below the floor of the RV. They generally have lockable doors to provide safe storage of larger possessions for which there is not enough space inside the RV. Some storage bays extend the full width of the RV with access doors on both sides and are referred to as "Pass Through Bays".

    Return to top of page

    Storage Pod (Roof Mounted):

    These are weatherproof modules mounted on the roof of an RV to provide storage space for goods not required on a regular basis, i.e. winter clothing, etc. They are usually made of plastic but may be constructed from metal. They are usually low profile and aerodynamically shaped to minimize drag.

    Return to top of page

    Tag Along:

    Any trailer using a standard ball mount hitch, e.g. a travel trailer. Supposedly these trailers just "tag along behind".

    Return to top of page

    Tag Axle: (View photo)

    An axle mounted behind the main drive axle of some motorhomes. It supports a portion of the load and adds to the vehicle's load carrying capacity.

    Return to top of page

    Tail Gunner:

    The tail gunner occupies the last vehicle in a caravan and is responsible for sweeping the route to make sure that none of the caravan members have been left behind due to equipment failure or any other reason. In professionally run caravans the tail gunner and the wagon master (see listing) are normally paid by the caravan's organizers. In smaller informal caravans, whomever is in last position in the line is the tail gunner by default and is normally not paid.

    Return to top of page


    The term used for an area or room in an RV that tips out for additional living space. The Tip-Out was generally used in older RVs. Newer RVs mainly use slide-outs (see listing).

    Return to top of page

    Tire Balancing:

    Correct tire balance affects stability and tire life. When the tire is out of balance, it will vibrate or bounce up and down as the wheel turns, possibly even lifting the tire off the road at times. If the out-of-balance tire is on a front wheel it often causes the steering wheel to shake or vibrate. Indications of a tire balance problem include shaking steering wheel, worn spots of the tread (referred to as scallops or cupping) and vibrations in the floor or seats.

    A common symptom of an out-of-balance condition is usually noticed at one particular speed and continued driving with out-of-balance tires can lead to premature shock absorber failure.

    Methods employed to balance tires include:
    • Lead weights attached to the wheel rim.
    • A powder such as Equal or ceramic beads such as Dyna Beads placed inside the tire.
    • A tubular device containing a liquid weight substance attached to the wheel along with the tire, e.g. the Centramatic.
    The advantage of dynamic methods such as powders, beads or liquids is that the tires stays in balance throughout its life. The more common lead weight system, on the other hand, has to be recalibrated periodically as the tire wears.

    Return to top of page

    Tire Manufacturing Date Codes:

    Generally accepted rules of thumb in the RV world are that regardless of low mileage or low tread wear, tires should be replaced every 5 to 7 years maximum. Exposure to sunlight, ozone, and ultra-violet radiation causes gradual loss of the plasticizers that keep the tires flexible. Sidewall cracking can often be seen but may not always be apparent. So, for the sake of safety and to avoid sudden catastrophic failure replacement should be done on an age priority basis. This does not mean that obvious tread wear, sidewall damage, or any other physical problem with the tires should be ignored if they still have x years to go before they are too old.

    The National Highway Traffic Safety Administration (NHTSA) Tire Identification and Record Keeping Regulation, revised July 2, 2000, specifies a new 4-digit date code that must appear on all tires sold in the United States. The complete DOT (Department of Transportation) code is in the following format: DOT MMM SS TTT DDDD where MMM is a 3 digit manufacturer ID; SS is a tire size 2 digit code; TTT is an optional tire type code; and DDDD is the date of manufacture code where the first 2 digits indicate the week of manufacture and the second two digits are the year, i.e.: 2802 would indicate that the tire was manufactured the 28th week of 2002. (View photo)

    Note: tires manufactured before July 2, 2000 had a 3 digit date code where the first 2 digits are the week of manufacture and the last digit is the year.

    It is strongly recommended that when buying new tires you insist on all tires having the same date of manufacture and that that date should not be more than a few months prior to the date of purchase. Otherwise you will be buying tires that will need to be replaced sooner than necessary.

    Return to top of page

    Tire Pressure Monitor:

    A system to continually monitor the air pressure in tires on an RV and either the towing vehicle (in the case of a trailer or 5th wheel) or the towed vehicle (in the case of a motorhome towing a car). The system is comprised of a sensor placed either on the valve cap of a tire or inside the tire, and a monitor panel placed on or near the dash. The sensors transmit the tire pressure to the monitor panel which alerts the driver in the event of air pressure in any tire falling by a specified amount below the starting pressure.

    Return to top of page

    Toad: (View photo)

    This is the term for a vehicle that you are towing with your motorhome. It is also known as a Dinghy.

    Return to top of page

    Tongue Weight:

    The weight that a travel trailer (tag alog) places on its coupler and therefore on the tow vehicle's ball hitch. It is typically 10-15% of the trailers loaded weight.

    Return to top of page

    Tow Bar or Tow Hitch: (View photo)

    A mechanism used for connecting a towed vehicle to the motorhome's hitch for towing with all four wheels on the ground.

    In the UK this style of tow bar is referred to as an A-frame, whereas the term tow bar as used in the UK refers to a tow hitch attached to the towing vehicle.

    Return to top of page


    A turning or rotational force. Generally speaking, diesel engines produce higher torque than their gas cousins, making them desirable for powering heavier motorhomes and for towing large (heavy) trailers. See also the listing for Horsepower.

    Torque is a measured value, expressed in pound feet (lb ft), whereas horsepower is a calculated value. As the saying goes, it's torque that gets you moving and gets you up the hills.

    Return to top of page

    Tow Dolly:

    A single-axle trailer used for towing a car that cannot be towed with all four wheels on the ground. Two wheels of the towed car sit on the trailer and the other two wheels will be on the ground. The tow dolly is attached to a tow ball on the rear of the motorhome.

    Return to top of page

    Toy Hauler:

    See listing under Recreational Vehicle Types.

    Return to top of page

    Toy Hauler Trailer:

    See listing for Toy Hauler under Recreational Vehicle Types.

    Return to top of page

    Toy House Trailer:

    See listing for Toy Hauler under Recreational Vehicle Types.

    Return to top of page

    Trailer Brakes:

    Brakes that are built into the trailer and are activated either by electric power from a brake controller on the towing vehicle (View photo) or by a surge mechanism.

    Return to top of page

    Trailer Life Campground Directory:

    Published by Trailer Life, this is a large telephone book sized listing of many campgrounds of all types covering the entire United States and Canada. Listings are alphabetical by state and city or area. Directions are given for access to the campground from the nearest highway or interstate highway. Amenities and types of hookups are listed along with the number of sites of each type and a rating (from 1 to 10 with 10 being best) for amenities, restroom/shower room completeness and cleanliness, and attractiveness of the camp and locale.

    These handy campground guides are available at many RV related stores and are updated annually.

    Return to top of page

    Train Weight:

    UK term for Gross Combined Weight Rating. See the entry for GCWR.

    Return to top of page

    Travel Trailer:

    See listing for RV Types.

    Return to top of page

    Truck Camper:

    See listing for RV Types.

    Return to top of page


    A turbo(charger) compresses the incoming air that is fed to the intake manifold of a diesel engine to create added boost. Operation of the turbo is relatively simple. The turbo has two sections, a turbine (drive) section, and a compressor (driven) section, both on the same drive shaft.

    The turbine section is driven by hot exhaust gases exiting the engine. Before the exhaust is allowed to travel out the tailpipe, it is forced to do work. That work is to spin the turbine. The turbine drives the compressor wheel which compresses the filtered incoming air.

    Air, at normal atmosoheric pressure, is compressed, exits the turbocharger, and travels through your intercooler (which is in front of your radiator) to remove excess heat. From there it goes into the intake manifold. The compressed air is now sitting on top of your intake valves. When the intake valve opens, pressurized cooled air enters the combustion chamber. Within design limits, the more air you can cram into the cylinder, the more fuel you can add, creating additional power. Turbocharging also insures that there is enough air to burn all the fuel completely, so there is less pollution released into the atmosphere.

    The only other major part of the turbo is the wastegate. The wastegate opens when the predetermined amount of boost pressure is exceeded. The wastegate opens, and gives the exhaust gases a direct path into the downpipe. The rerouted exhaust gases bypass the turbine, so the turbo loses some of it's "drive". It slows down and reduces the amount of boost. When the boost pressure falls below the wastegate setting, the gate closes and now all the exhaust gases are once again driving the turbine.

    Return to top of page


    British term for tire; The kind your vehicles ride on and that you put air in.

    Return to top of page

    Unladen Weight):

    UK term for Unloaded Vehicle Weight. See listing for UVW.

    Return to top of page

    UVW (Unloaded Vehicle Weight):

    UVW is the weight of the RV as built at the factory with full fuel, engine oil and coolants. The UVW does not include cargo, fresh water, LP Gas, occupants or dealer installed accessories.

    Return to top of page

    Unsprung Weight:

    For any single axle this is the weight of the tires, wheels, brakes, axle, and any other equipment attached to the axle and that is not directly attached to the chassis of the vehicle. In the case of the drive axle, this includes the weight of the differential gears and their housing.

    Return to top of page


    US Forest Service. The entry for Campgrounds for an explanation of USFS campgrounds.

    Return to top of page

    Utility Bay:

    An exterior bay on many RVs in which the various liquid utility hook-ups are located. In some cases the bay is heated to prevent freezing of the hook-ups in cold weather. Frequently the sewer connection is located in this bay with an exit hole for the hose in the floor of the bay. A screw-in plug normally closes this hole while the RV is under way.

    Return to top of page


    A word commonly used to refer to a class/style of vehicle. In the RVing sense, it usually refers to a van that has been converted to include sleeping/living accommodation.

    An alternative useage, almost exclusively in Great Britain, it's an abbreviation of caravan, the word used there to describe house trailers, travel trailers, or fifth wheel trailers. Over time it has become a more generic term in the UK, used for various types of trailers and motorhomes.

    Return to top of page

    VIN (Vehicle Identification Number):

    A unique serial number assigned by a vehicle manufacturer. In the case of a motorhome built on a chassis from a different manufacturer, the VIN is assigned to the chassis.

    Return to top of page

    Wagon Master:

    The wagon master occupies the first vehicle in a caravan (see listing) and is responsible for leading and setting the pace for the route. The tail gunner (see listing) and the wagon master are normally paid by the caravan's organizers in professionally run caravans. In smaller informal caravans whomever is most familiar with the route and destination is chosen as the wagon master.

    Return to top of page

    Weight Carrying Hitch:

    A hitch designed to accept the entire hitch weight of the trailer. This hitch is also known as a dead weight hitch.

    Return to top of page

    Weight Distributing Hitch:

    A hitch that utilizes spring bars that are placed under tension to distribute a portion of the trailer's hitch weight to the tow vehicle's front axle and the trailer's axles. This hitch is also known as an equalizing hitch

    Return to top of page

    Weight Ratings:

    The maximum allowable weight specifications of an RV. These ratings are specified on a Federal Weight Certification sticker and a RVIA-approved sticker located inside the RV. See also Gross Axle Weight Rating (GAWR), Gross Combined Weight Rating (GCWR), Gross Vehicle Weight Rating (GVWR), and Sleeping Capacity Weight Rating (SCWR).

    Return to top of page

    Wet Cell:

    See listing for Battery Types.

    Return to top of page

    Wet Weight:

    Wet Weight is the weight of the RV with oil in the engine and with full fuel, freshwater, gray water, black water and propane tanks.

    Return to top of page


    The distance between the center of the steer axle and drive axle on single axle vehicles. On vehicles with a tag axle, the measurement is taken from the center of the steer axle to a point midway between the centers of the tag and drive axles.

    Return to top of page

    Wide Body:

    The term for an RV exceeding the former normal 96" (8' 0") width body style. Wide Bodies are usually 100" (8' 4") to 102" (8' 6") wide. Virtually all newer type A and type C coaches are wide body style now.

    Return to top of page


    A technology that allows electronic devices to communicate without the need for wires connecting the individual devices. The correct use of the term WiFi is for products that have been certified by the WiFi Alliance.

    WiFi allows an RVer to connect their personal computer wirelessly to a local area network in order to connect to the internet. Devices that allow a PC to communicate in this manner include an external wireless card plugged into a PC, an internal wireless adapter inside a PC, and an external wireless adapter.

    Return to top of page

    Wild camping:

    Wild camping is another name for boondocking. See the boondocking entry for more information.

    Return to top of page

    Wind Turbine:

    Wind turbines are another source of power available while boondocking (see listing). They are available in a number of sizes and capacities. They consist of a weatherproof power head containing a generator that is connected to the propeller drive shaft via gearing or belt(s). At the rear of the power head is a vane that orients the power head so that the propeller faces into the wind. The power head is free to swivel atop a mounting mast so that the wind vane aims the unit into the wind for maximum efficiency. The propeller is attached to the power head's drive shaft and generally has 2 to 4 blades.

    These units are relatively large and must be firmly supported with the mounting mast in a vertical position. In most cases guy-wires are required.

    Raw power output varies with wind speed but a control unit prevents over charging of the batteries and regulates power from the unit to the battery bank.

    Return to top of page


    A process of making an RV safe from the hazards of winter storage in cold climates. The process could involve draining fresh water and waste storage tanks, draining the water heater, and blowing residual water out of water lines. It may also involve introducing a special antifreeze into the tanks and water system.

    Return to top of page


    See the listing for WiFi.

    Return to top of page

    Woodall's Camping Guide:

    This is a large telephone book sized listing of many campgrounds of all types covering the entire United States and Canada. Listings are alphabetical by state and city or area. Directions are given for access to the campground from the nearest highway or interstate highway. Amenities and types of hookups are listed along with the number of sites of each type and a rating for amenities, restroom/shower room completeness and cleanliness, and attractiveness of the camp and locale.

    These handy campground guides are available at many RV related stores and are updated annually.

    Return to top of page


    Workamping can either defray expenses or actually be a job with a positive cash flow. In most cases it is a part time job where you can live and work in the same place, but may be more. It is a popular way to help support the RV habit. Workamping assignments are typically 2-3 months in duration but may be for the entire season in some areas. Duration and method of compensation are usually negotiable.

    There are three types of workamping positions. Some workamping jobs are volunteer positions, with the camper receiving a free campsite in exchange for their presence the park, often just to greet people and answer questions. These are often termed campground host positions. Other workamping jobs are barter arrangements, where the camper receives a campsite and perhaps other benefits in payment for campground work, such as 20 hours/week collecting site fees or cleaning the bath house, etc. The distinction between volunteer and barter is largely for tax purposes and not a practical difference for most workampers. The third type is a regular job, where the workamper is paid an hourly rate for whatever work is assigned and in turn pays for his campsite at the going rate, usually the seasonal or long term rate. In the third type the worker's presence in the park is not part of the job - you could camp/live elsewhere if you chose. An example might be a camp office job or leader of an activity such as craft classes. Often a position is a blend of the second and third type, with part of the work done as barter for the campsite and "extra" work done for cash.

    There are agencies that assist campers and campground owners find each other, e.g. www.workamper.com and Workamper News, but often workamping jobs are simply found, either by word-of-mouth or simply asking at the campground office when you find a place you enjoy and want to stay awhile. A campground is a 24/7 operation for the owner, so they almost always need some extra help. State and local parks may advertise on their web sites and at park offices. Finally, there are companies whose business is campground/park management and they contract to provide staff and management. Many federal & state parks are operated this way. One such is Recreation Resource Management (RRM) and they advertise positions through their website, http://www.camprrm.com/ . Chains like KOA and Jellystone parks also advertise through their websites and newsletters.

    Return to top of page

    Contributors to the content &/or photos include Gary Brinck, Jim Dick, Don Jordan, Carl Lundquist, Judy Madnick, Steve Pally, Ned Reiter, Paul (aka janpaul), Ron Ruward, Fred Thomas, Tom Jones, et al.

    Please report errors or suggest additions to this glossary here

    (C) 2003, 2004, 2007, 2008, 2009 The RV Forum.