RV Terms and Definitions

A glossary of Common RV related terms with their definitions used within the RV industry.


AC is 120-volt alternating current (same as in houses).


Air Conditioning unit.

Anode Rod

An anode rod, when used in a water heater, attracts corrosion causing products in the water. These products attack the anode rod instead of the metal tank itself. The anode rod should be inspected yearly and changed when it is reduced to about 1/4 of its original size. The rods are used in steel water heater tanks – an aluminum tank has an inner layer of anode metal to accomplish the same thing. Anode rods should not be installed in an aluminum tank!

Arctic Package

A feature on an RV that adds additional insulation, storm windows and heat pads/strips for the holding tanks and water lines, to enable the RV to be used in cold weather.

Axle Ratio

The ratio between the pinion and ring gears in the differential that multiply the torque provided by the engine. It is the number of driveline revolutions required to turn the axle one time. As an example, with a 4.10:1 axle the driveline turns 4.1 times for each full axle revolution. The higher the number, the more torque and thus more towing power. However, the higher the number the slower your vehicle speed.

Backup Monitor

A camera in the back of a motorhome, with the monitor positioned somewhere on the dashboard for the driver, to aid in backing up the motorhome. It is also used while driving to see the traffic behind and to keep an eye on your towed vehicle.

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.


The storage area below the floor of the RV, accessible from the outside. Basement storage usually refers to storage in a Class-A or Class-C motorhome.

Black Water

Disposal water from toilet system, held in holding tank until you dump it, in large tanks or dumping station available at most campgrounds.

Black Water Tank

The black water tank on an RV holds the sewage water from the toilet. This should always be dumped at a campgrounds dump station or into the campsite sewer connection.


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 from your RV batteries and water from your freshwater holding tank.

Brake Controller

A control unit mounted inside the vehicle that allows the electric brakes on the trailer to become activated in harmony with the braking of the tow vehicle. The controller can also be used to manually activate the trailer brakes.

Break-Away System

A system designed to automatically lock the trailer brakes in the event of a hitch failure, where the trailer may break away from the tow vehicle.

British Thermal Unit (BTU)

A measurement of heat that refers to the quantity required to raise the temperature of one pound of water one degree F. (Fahrenheit). RV air conditioners and furnaces are BTU-rated.

Bunk House

RV’s with a section set aside with bunk beds. This allows sleeping room for a larger number of people.


The part of a Class C motorhome that extends over the top of the vehicle’s cab, usually containing a sleeping or storage space.

Chassis Battery

The battery used to start the engine in a motorhome. It is usually only charged when the engine is running. It is separate and apart from the House batteries that are used to power various appliances in an RV. Only Motorhomes need a chassis battery.

City Water

A generic term for using water from an outside source, such as a campground spigot, instead of water held in the internal freshwater tank.


Front of your motorhome where the driver pilot seat and passenger co-pilot seats are located.


Condensation is a result of warm moisture-laden air contacting the cold window glass. Keeping a roof vent open helps to reduce the humidity levels. Added roof vent covers help to prevent cold air from dropping down through the vent while still allowing moist air to escape. Using the roof vent fan when showering or the stove vent fan when cooking also helps prevent excess moisture buildup.


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-volt DC.


The part of the trailer that attaches to the ball of the hitch.

Cut-off Switch

An electrical switch that will cut off power to the ‘house’ portion of the RV. This is to prevent battery drain when you are not using the RV. If you will store it for an extended period, it is best to disconnect and remove the batteries for storage in a cool, dry place.


DC is 12-volt direct current (same as in motor vehicles)

Diesel Puller

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

Diesel Pusher

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


Booth-like dining area. The table usually drops to convert the unit into a bed at night.


The term for a vehicle that you are towing with your motorhome. It is also known as a Toad


A rubber ring that seals one’s dump hose and the campsite sewer connection so that gases and odors do not escape. Sewer doughnuts are required in many locations.

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 from your RV batteries and water from your freshwater holding tank.

DSI Ignition

Direct spark ignition – this term refers to the method of igniting the main burner on a propane-fired appliance. The burner is lit with an electric spark and the flame is monitored by an electronic circuit board. This ignition system is used in refrigerators, furnaces, and water heaters. There is now a version of stovetops that light the burners with a DSI ignition.

Dual Electrical System

RV equipped with lights, appliances which operate on 12-volt battery power when self-contained, and with a converter, on 110 AC current when in campgrounds or with an onboard generator.


A pickup truck, or light-duty tow vehicle, with four tires on one rear axle.

Ducted AC

Air conditioning supplied through a ducting system in the ceiling. This supplies cooling air at various vents located throughout the RV.

Ducted Heat

Warm air from the furnace supplied to various locations in the RV through a ducting system located in the floor. (similar to house heating systems)

Dump Station

A facility for dumping or emptying your black water and gray water holding tanks.

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


Another name for a fifth-wheel RV.


Family Motor Coach Association

Fresh (Water) Tank

The gallons of freshwater that can be stored for later use

Full Hookups

The ability to connect to all three of the campground’s facilities; electric, water, and sewer.

Fulltimers or Fulltiming

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


This term refers to the kitchen of your RV.


An electrical device powered by gasoline or diesel fuel, and sometimes propane, for generating 120-volt AC power. Also known as Genset.

Gray (Water) Tank

The gallons of gray waste that can be held in the RV. Gray water is waste from the sinks and shower.

Gray Water

Disposal of water from sinks, shower. In some units, this is held in a tank separate from black water; is also dumped in tanks at campgrounds

Heat Exchanger

A heat exchanger is a device that transfers heat from one source to another. For example, there is a heat exchanger in your furnace – the propane flame and combustion products are contained inside the heat exchanger that is sealed from the inside area. Inside air is blown over the surface of the exchanger, where it is warmed and the blown through the ducting system for room heating. The combustion gases are vented to the outside air.

Heat Strip

A heat strip is an electric heating element located in the air conditioning system with the warm air distributed by the air conditioner fan and ducting system. They are typically 1500 watt elements (about the same wattage as an electric hair dryer) and have limited function. Basically they “take the chill off”

Holding Tanks

There are three different holding tanks on most RVs: Fresh Water, Gray Water and Black Water. The freshwater tanks hold the water you will use for water you will pump into your RV when you are not getting water from an outside source. The Gray Water tank holds water from your kitchen and shower. The black water tank holds the water and waste from your toilet.


The ability to connect to a campground’s facilities. 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.

House Battery

These batteries are used to supply 12vdc and limited 120vac (from the Inverter) to the various outlets and appliances of an RV. This includes lighting. These batteries are separate and apart from the Chassis battery in a motorhome.

Hula Skirt

A skirt placed on the back bumper of a motorhome to stop debris that is thrown from the rear wheels from damaging vehicles behind the motorhome, either the vehicle you are towing or other vehicles behind the motorhome


An electrical device that changes 12-volt battery power to 120 volt AC power. It is used when “boondocking” (camping without hookups) to power certain 120 VAC only devices like a microwave oven. The amount of available power depends on the storage capacity of the batteries and the wattage rating of the inverter.

Island Queen

A queen-sized bed with walking space on both sides.


A sandwich of structural frame members, wall paneling, insulation, and exterior covering, adhesive-bonded under pressure and/or heat to form the RV’s walls, floor and/or roof.

Leveling Jacks

These will make sure your RV sits level on the ground.

LP Gas

Liquefied Petroleum Gas. LP gas is used to fuel appliances in the RV, such as the stove, oven, water heater and refrigerator. Propane tanks are usually rated as pounds or gallons

Motor Coach

A motorhome that is built on a bus-type chassis.


Any type of RV that has a built-in motor such as Class A, Class B, Class C, etc.

Navy Shower

There are times in an RV when you want to conserve water or there is not enough hot water to go around. In such times people may use the water to get wet, turn off the water, ‘lather up’ or wash and then turn on the water to rinse. Modern RV hot water heaters are fast, but when four or five campers have to take a shower, this method speeds things up.


Someone who is either new to RVing, or new to a specific type of RVing. 


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.

Patio Mat

Carpet or woven mat for use on the ground outside of RV. Used whether or not a concrete patio pad is available where camping.


A pilot is a small standby flame that is used to light the main burner of a propane fired appliance when the thermostat calls for heat. Pilots can be used in furnaces, water heaters, refrigerators, ovens and stove tops.


The term for a room in an RV that pops out for additional living space.

Popup or Pop-Up

Another name for a folding camping trailer.


A term used to define the up and down motion in an RV while traveling.

Primative Camping

Camping without use of hookups.


LPG, or liquefied petroleum gas, used in RVs for heating, cooking and refrigeration. Also called bottle gas, for manner in which it is sold and stored.

Pull Through

A camping site that allows you to pull through while setting up and leaving the area. A site where you do not have to back into or out of.


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


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


The part of the hitch that permits a hitch bar to be inserted.


A slang term for the refrigerator in your RV.


What many RVers call their units.

Roof Air Conditioning

Air conditioning unit mounted on the roof of the RV, to cool the RV when it is parked. When moving, most RVs are cooled by separate air conditioning units which are components of the engine, or they may be cooled by a rooftop if a proper size generator is installed.


Short for Recreation Vehicle, a generic term for all pleasure vehicles which contain living accommodations. Multiple units are RVs and persons using them are RVers.


Recreational Vehicle Dealers Association


Recreational Vehicle Industry Association


Recreational Vehicle Rental Association

Safety Chains

A set of chains that are attached to both the trailer A-Frame and the tow vehicle while towing. Safety chains are intended to keep the trailer attached to the tow vehicle in the event of a hitch failure, preventing the trailer from completely separating from the tow vehicle.

Screen Room

The term for a screen enclosure that attaches to the exterior of an RV for a bug-free living area outside.

Self Contained

RV which needs no external electrical, drain or water hookup. Thus, it can park overnight anywhere. Of course, self-contained units can also hook up to facilities when at campgrounds.

Semi-Modern Camping

Camping with partial hookups, usually just electrical.

Sewer Doughnut

A rubber ring that seals one’s dump hose and the campsite sewer connection so that gases and odors do not escape. Sewer doughnuts are required in many locations

Shore Power

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


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


Room or area in your RV that slides out to make additional space for living.


The slang term for a slider-hitch.

Slider Hitch

A sliding hitch used on short-bed pickup trucks to enable them to tow fifth-wheel trailers. It allows them sufficient clearance to make turns without having the trailer hit the cab of the truck.

Super Slide

This refers to one large slide that can expand the entire living area of an RV. This is more common in large Motorhomes and Fifth Wheels.

Sway Bar

Hitch system designed to reduce or eliminate side to side sway movement of your trailer.


A device that monitors the pilot flame of a pilot model propane appliance. If the pilot flame is extinguished the thermocouple causes the gas valve to shut off the flow of gas to both the pilot flame and the main burner.


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 a slide-out.


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

Tow Bar

A bar used for connecting a towed vehicle to the motorhome for towing with all four wheels on the ground.

Trailer Brakes

Brakes that are built into the trailer and are activated either by electric impulse or by a surge mechanism.

Transmission Cooler

A heat exchanger is similar to a small radiator through which automatic transmission fluid passes and is cooled.

Triple Towing

The term used for three vehicles attached together, usually a tow vehicle pulling two separate trailers. A typical configuration might be a tow vehicle pulling a travel trailer with a boat behind that.


The RV’s underfloor surface, which is protected by a weatherproofed material.


The leader, either hired or chosen, who guides a caravan of recreational vehicles on a trip. The wagonmaster usually makes advance reservations for campgrounds, shows, cruises, sightseeing and group meals.

Waste Water Tanks

The gray water tank holds the wastewater from the sinks and showers. The black water tank holds the waste from the toilet.


RVers that use their RV on the weekends throughout the year.

Weight Carrying Hitch

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

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.


The distance between center lines of the primary axles of a vehicle. If a motorhome includes a tag axle, the distance is measured from the front axle to the center point between the drive and tag axles.

Wide Body

The term for an RV exceeding the normal eight feet wide. Wide Bodies are usually 102″ (8′ 6″) wide.


To prepare the RV for winter use or storage. This is done to avoid damage due to colder temperatures.

Work-Camper (Workamper)

This is a system where people who live in an RV full time can move from place to place and find jobs in RV parks, National or State Parks or other venues. Part of the pay is often free or reduced parking fees.