Definition of RV Terms

120v AC/12v DC/LP-Gas – The power sources on which RV refrigerators operate; 120v AC is 120-volt alternating current (same as in houses); 12v DC is 12-volt direct current (same as in motor vehicles); LP-gas. Some RV refrigerators can operate on two of the three sources, others on all three.

4 Pin Electrical Connector – This provides power from your tow vehicle to your RV for the lights only.

7 Pin Electrical Connector – This provides power from your tow vehicle to your RV for the lights as well as the electrically operated brakes.

A/C – Air conditioner.


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.

Auxiliary Battery – An extra battery to run your 12-volt equipment.

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 also means less speed.

Backup Monitor/Camera – 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 the 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.

Basement – The large storage area underneath your RV’s floor accessible from outside storage doors.

Black Tank – The Black Tank holds body waste directly from the toilet. It is usually one of the smaller tanks in an RV. A 40-gallon tank will last one average person about three weeks. This depends very much on use.

Black Water – Waste contained in the Black Tank. This should be considered as and treated as raw sewerage. Always wear rubber surgical gloves when dealing with the sewer system.


Blueboy/Blue-Boy – Term for portable waste holding tank, often this plastic tank comes in a bright shade of blue, hence the term.

Boondocking – This is a style of camping that refers to having no hook-ups for power, water or sewerage. It was more common in the early days of camping when such facilities were limited. Today it is more of a choice. When Boondocking you are limited to the power in your batteries, the water in your white tank and the capacity of your Gray and Black tanks.

Brake Actuator – a device mounted under the dash of a towing vehicle to control the braking system of the trailer. Most Brake Actuators a based on a time delay, the more time the tow vehicle brakes are applied the “harder” the trailer brakes are applied.

Brake Controller – a device mounted under the dash of a towing vehicle to control the braking system of the trailer. The Brake Controller senses the amount of braking force of the tow vehicle and applied a proportional force to the trailer braking system.

British Thermal Unit (BTU) – A measurement of heat that is the quantity required to raise the temperature of one pound of water 1 degree F. RV air-conditioners and furnaces are BTU-rated.

Bubble level

Break-Away System – A system designed to automatically lock the trailer brakes in the event of a hitch failure and the trailer breaks away from the tow vehicle.

Bubble – Can refer to either a bubble level for determining when the RV is level, or a bubble under the exterior skin of an RV indicating some delamination.

Bunk House – These are RV’s with a section set aside with four to eight bunk beds. This allows sleeping room for a larger number of people.

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

Camber – Wheel alignment – Camber is the number of degrees each wheel is off of vertical. Looking from the front, tops of wheels farther apart than bottoms means “positive camber”. As the load pushes the front end down, or the springs get weak, camber would go from positive to none to negative (bottoms of wheels farther apart than tops).

Camper Shell – Removable unit that sits in the bed of a pickup truck.

Cassette Toilet – Toilet with a small holding tank that can be removed from outside the vehicle in order to empty it.

Castor – Wheel alignment – The steering wheels’ desire to return to center after you turn a corner.

Class A motorhome

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 – We use this as a generic term meaning we are using water from an outside source, such as a campground spigot, instead of water held in the internal fresh water tank.

Class A – This is a Bus style RV. These are the largest type of motorhome. They can be gas or diesel, with the engine in the front or rear.

Class B – These are often referred to as Conversion Vans. That is an older terminology. They are a small motorhome that looks like a large van with some limited RV fixtures installed.

Class B motorhome

Class C – These motorhomes have the appearance of a long body pick-up with the bed removed and an RV section built on. They usually have a section that extends over the cab of the truck.

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

Condensation – 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.

Class C motorhome

Converter – An electrical fixture on most RV’s. These take 120vac (house type current) from shore power, or your generator, to provide 12vdc for those appliances in the RV that need 12vdc, and to charge the batteries. In many RV’s the Inverter and Converter are two parts of one component. (See section on Electrical System).

Cut-Off Switch – Most RV’s have a switch somewhere 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.

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.

Dinette – Booth-like dining area. Table usually drops to convert unit into a bed at night.

Dingy – Common slang for a towed vehicle, TOAD.

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.

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.

Dry Weight (DW) – The weight of the RV without any fuel, freshwater, propane or passengers.
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 stove tops that light the burners with a DSI ignition.

DSI Ignition – Direct Spark Ignition. This term is used to describe the method of igniting the main burner on a propane fired appliance.

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.

Dually – A large pickup truck with two sets of side by side wheels in the rear. This gives extra towing capacity and better traction.

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 fu

Dump station

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

Dumping Tanks – This refers to emptying the Gray and Black tanks in an RV.

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

East-West – This refers to a bed in an RV that runs sideways in an RV. For example, the head of the bed is toward the left side of the RV and the foot is toward the right side. This is different from a North-South bed that goes lengthwise, front to back.

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.

Fifth wheel trailer

Fifth Wheel – a common RV that is towed behind a truck. A fifth wheel can be distinguished from a Travel Trailer by the fact that the front of the unit extends up and over the bed of the truck and is hitched in the bed, not on the back bumper.

Fire Ring – Areas designated by some campgrounds for building small fires. This is where you roast wienies and marshmallows!

Fiver – Common slang for a fifth wheel trailer.

Fresh (Water) Tank – The gallons of fresh water that can be stored for later use.

Full Hook-Ups – Generally refers to a campsite that has connections for electric, fresh water, and sewage. It may include telephone and or cable TV.

Fulltimers Photo courtesy of roadslesstraveled.us

Fulltiming or Fulltimers – This describes a person who lives in an RV all the time, not just a few weeks at a time. This is the case with some retired people who just go on the road for a few years or decades. Some people full time for other reasons, such as a job that moves them about.

Galley – This term refers to the kitchen of your RV.

Generator – A unit that will provide auxiliary electrical power to an RV. Various size units provide 120vac. These units are measured in Watts of output. They may be portable or built into the RV. They may run on Gasoline, Propane or Diesel.


Genset – Common slang for a Generator

Gray Tank – This tank holds the waste water from the sinks and shower.

Gray Water – This is the water that has been used for washing clothes, showers or in a sink. It is not really sewage, but it is not fit for re-use. It is stored in the Gray Tank.

Gross Axle Weight Rating (GAWR) – The manufacturer’s maximum load weight, in pounds, that can be placed on the axle. If an axle has a 3500-lb. GAWR and the RV has two axles (tandem axles), then the RV would have a Gross Vehicle Weight Rating (GVWR) of 7000 lbs. (see GVWR  below)

Gross Combined Weight (GCW) – The combined weight of the tow vehicle and the trailer.

Gross Combined Weight Rating (GCWR) – The manufacturer’s maximum load weight, in pounds, allowed for the trailer and tow vehicle. This rating includes the weight of the trailer, tow vehicle, fuel, water, propane, supplies, and passengers.

Gross Trailer Weight (GTW) – Gross trailer weight is the weight of the trailer fully loaded in its actual towing condition. GTW is measured by placing the fully loaded trailer on a vehicle scale. The entire weight of the trailer should be supported on the scale.

Gross Vehicle Weight (GVW) – The weight of the vehicle.

Gross Vehicle Weight Rating (GVWR) – The manufacturer’s maximum load weight, in pounds, allowed for the vehicle. This rating includes the weight of the vehicle plus fuel, water, propane, supplies, and passengers.

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 then 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”

Hi-Low – These are travel trailers that collapse from full to about half height. They offer less wind resistance and are therefore viewed by some as being more economical to tow. Otherwise, they have all the amenities of a normal Travel Trailer.

Hitch Weight – 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.

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.

Hookups – refers to facilities in a campground that can supply electrical power or water and provide a place to connect a sewer hose for dumping.

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.

Inverter – An electrical box that takes 12vdc from the House batteries and supplies limited 120vac to selected outlets in an RV. Depending on what you choose to run this way, the batteries will be drained rapidly of power. (This does not usually affect the starter battery in a motorhome. In many RV’s the Inverter and Converter are two parts of one component.

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

Laminate – 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.

Livability Packages – items to equip a motorhome for daily living, which may be rented at nominal cost from a rental firm, rather than brought from home. Include bed linens, pillows, and blankets, bath towels, pots and pans, kitchen utensils, cutlery.

LP Gas – Liquefied Petroleum Gas. LP gas is used to fuel appliances in the RV, such as the stove, oven, water heater and sometimes the refrigerator. Often called propane. LP weighs 4.5 pounds per gallon.

Military (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.


Motorcoach – Term for motorhome on “bus” type chassis.

Motorhome – (MH) – Any type of RV that has a built-in motor. There are various types, such as Class A, Class B, Class C, etc.

Navy Shower – See Military Shower

Net Carrying Capacity (NCC) – Sometimes called the payload capacity, this is the maximum weight of fuel, water, propane, supplies, and passengers that can be added to an RV without exceeding the Gross Vehicle Weight Rating (GVWR). (see GVWR above)

Newbie – a person who is either new to RVing, or new to a specific type of RVing. Keep one thing in mind, we were all newbies once.

Nonpotable water – Water not suitable for human consumption or filling your fresh water tank.

North-South – This refers to a bed in an RV that runs lengthwise in an RV. For example, the head of the bed is toward the back of the RV and the foot is toward the front. This is different from an East-West bed that goes from side to side.

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.

Patio mat

Park Model – This is a type of RV made to be permanently parked in an area.

Part-Timers – 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.

Payload Capacity – The maximum allowable weight that can be in or on a vehicle, including all cargo and accessories, fuel, freshwater, propane, passengers and hitch loads.

Pilot – 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 stovetops.

Pop-Out – The term for a room in an RV that pops out for additional living space.

Pop-up trailer

Pop-Up – This is a hybrid camper that is part trailer and part tent. It is towed behind a car or truck as a small, flat-topped trailer. When parked it can be cranked open to reveal a tent that is up off the ground.

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

Primitive camping – Also known as “dry camping” or boondocking. Camping without the modern convenience of full-hookup facilities like city/well water, sewer/septic, and electricity. Primitive campers rely on ‘onboard’ systems for these conveniences; generator, batteries, waste tanks, stored water, etc.

Propane – A compressed gas used for various purposes in an RV. It is used to heat water, run a furnace and even cool a refrigerator. It is contained in tanks of various sizes that are either portable or permanently mounted in an RV.

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

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.

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

Rig – What many RVers call their units.

Roof Air Conditioning – air conditioning unit mounted on the roof of an 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.

RV – Recreational Vehicle. Any of the many designs of vehicles or trailers used by people to camp in. The most common are Motorhomes, Fifth Wheels, Travel Trailers, Vans or Pop-Ups.

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

Screen room – Term for screen enclosure that attaches to the exterior side of an RV for a bug and rain-free outside sitting area.

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.

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 – Refers to an electrical hook up found at campsites. When you connect a cable from the campground receptacle to your RV, shore power supplies 120vdc (house current) to your RV. This commonly comes in either 30 amp or 50 amp. Most campgrounds have one electrical “post” with both connectors. The plugs are different, so you cannot connect to the wrong one. After connecting, flip the circuit breaker on. (See Camp Ground Set Up).

Truck (slide in) camper

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

Slide-Out – A room or area in your RV that slides out to make additional space for living.

Slider Hitch – A fifth wheel hitch that is best for short bed pick up trucks. It allows for tighter turns without letting the side of the fiver damage 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 System – Designed to reduce or eliminate side to side sway movement of your trailer.

Thermocouple – 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.

Tip-Out – 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.

Toad – This is an abbreviation for your Towed Vehicle…Towed = TOAD. This is not the truck you tow a trailer or Fiver with, but a vehicle you tow behind a motorhome to have transportation while the RV is parked.

Tongue Weight – This is the actual weight pressing down on the hitch ball(located on the tow vehicle). Generally 10% – 15% of the GVW.

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

Tow Rating – The maximum weight your tow vehicle can safely tow (set by the vehicle manufacturer).

Toy Hauler – This style of RV, usually a Fifth Wheel, has a partitioned area in the rear with a loading ramp that allows for the storage, loading and unloading of ‘Toys”, such as motorcycles or ATV’s.

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 similar to a small radiator through which automatic transmission fluid passes and is cooled by airflow.

Travel trailer

Travel Trailer – A type of towed RV that is distinguished by the way it hitches to the tow vehicle. The hitch is attached to the back of a vehicle, not the bed.

TT – Common slang for a travel trailer.

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

Unloaded Vehicle Weight (UVW) – Sometimes called the Dry Weight, it is the weight of the RV without adding fuel, water, propane, supplies, and passengers. The manufacturers UVW will not include any dealer-installed options.

VAC – Volts Alternating Current. Commonly called House Current.

VDC – Volts Direct Current.

Wagonmaster – A 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.

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

Wastewater tanks – The gray water tank holds the waste water from the sinks and showers. The black water tank holds the waste from the toilet.

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.

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.

Weights – What weighs what?

  • Propane weighs 4.25 pounds per gallon
  • Water weighs 8.3 pounds per gallon
  • Gasoline weighs 6.3 pounds per gallon
  • Diesel fuel weighs 6.6 pounds per gallon

Wet Weight – The weight of the RV with the fuel, freshwater and propane tanks full.

Wheelbase – 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.

White Tank – The tank that holds your potable drinking water. This is usually the largest tank in an RV. This water is used for washing machines, showers, sinks, etc.

White Water – This is clean, fresh water suitable for drinking or showering. This comes either from the White Water tank or from an outside water spigot connection.

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

Winterize – To prepare the RV for winter use or storage.

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. You can visit the website www.workamper.com to learn more about this resource.

Yaw – Fishtailing action of the trailer caused by external forces that set the trailer’s mass into a lateral (side-to-side) motion. The trailer’s wheels serve as the axis or pivot point. Also known as “sway.”

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