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

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

Amp: Amp is short for ampere, the electric current unit of measure. RV sites with electrical hookups will specify the maximum amps supported – which generally come in units of 20, 30, or 50 amps. The RV power connector must match the various plugs of the site amp rating.

Anode Rod: When used in a water heater, an anode rod 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.

Articulation Point: A joint between two objects which allows movement. In the case of RV’s, an articulation point is where two vehicles are coupled together by a ball or fifth wheel hitch. When a truck is pulling a travel trailer or fifth wheel, a single articulation point exists. If a boat is towed behind the trailer then two articulation points exist.

Awning: A roof-like structure made of canvas or other artificial materials that extends from the RV body to provide shade. Awnings are generally placed over entrances. Some extend and stow manually while others are operated electrically.

Axle ratio: Ratio between pinion and ring gears in the differential that multiply torque provided by the engine. It describes the number of driveline revolutions required to turn the axle one time. With a 4.10:1 axle, the driveline turns 4.1 times for each full axle revolution. Higher numbers mean more torque and less road speed for a given engine speed; i.e., a 4.10:1 ratio provides more torque than a 3.73:1.

Back In: A slot in an RV park with a single entrance, designed to be backed into with the RV.

Basement: The storage compartment of RV’s under the main living area. Basements are generally found on motor homes and fifth-wheel trailers.

Batwing Antenna: TV antenna on the roof on an RV characterized by two horizontal elements. Batwing antennas are generally raised and rotated with a hand crank from inside the RV living compartment.

Black Water: Wastewater (sewage) from a toilet system held in an onboard holding tank until a means of disposal is available.

Black Tank: See Black Water above

Boondocking: Camping without hookups. Strictly speaking, boondocking is camping far away from civilization without any facilities such as water or electricity; roughing it. In a more general sense, it has come to mean camping or parking anywhere without facilities, relying strictly on the comforts provided by the RV. Many RVers refer to spending the night in an interstate rest area, shopping center parking lot, or truck stop, as boondocking. The term is also used among campers who like to enjoy nature at its fullest, regardless of the terrain, and avoid commercial campground fees.

British Thermal Unit: (BTU) A measurement of heat that is the quantity required to raise the temperature of one pound of water 1 degree Fahrenheit. RV air-conditioners and furnaces are BTU-rated. A one-ton Air conditioning unit is the equivalent of 12,000 BTU.

Camper: Another term for an RV, especially smaller RV’s that are towed behind or carried on top of light trucks. Truckers generally refer to all RV’s as “campers” in their CB conversations.

Caravan: A group of three or more RVs traveling together. Like a miniature version of a 16-wheeler “convoy”.

Cargo Weight: Cargo Weight is the actual weight of all items added to the Curb Weight of the vehicle or trailer. This includes personal cargo, optional equipment, and Tongue or King Pin Weight.

CB Radio (CB): Citizens Band radio is a general use, short distance, two-way radio primarily used by truckers. CB’s are also helpful to RV drivers to call for help in an emergency and listen for driving conditions. Many of CB’s on the market today also have weather channels with alerting features.

Castor (Wheel Alignment): A steering wheel’s tendency to return to the dead center after the driver turns a corner.

Chassis: The frame of a vehicle or motor home including the engine, transmission, drive train, axles, and wheels. When referring to a van or truck, the chassis also includes the cab.

Chassis Battery: Battery in motor homes and tow trucks for operating the engine and vehicle components. Gas engine vehicles generally have one chassis battery and diesel two. Also referred to as the starting battery.

Class A Motorhome: A motor home built on a stripped truck chassis where the driving compartment is an integral part of the RV interior. Class A motor homes look like busses. Models range from 24 to 45 feet long.

Class B Motorhome: Also known as a camping van conversion. These RVs are built within the dimensions of a van, but with a raised roof to provide additional headroom. Basic living accommodations inside are ideal for short vacations or weekend trips. Models usually range from 16 to 24 feet.

Class C Motorhome: A motor home built on a cut-away van or truck chassis, including the cab. It differs from the class A motor home in that class C uses the cab designed for the chassis. A full-size bed in the “cabover” section allows for ample seating, galley and bathroom facilities in the coach. Also called a “mini-motorhome” or “mini.” Lengths range from approximately 16 to 32 feet

Coach: A vehicle with enclosed passenger accommodations. In the broadest sense of the term, the coach can be applied to most recreational vehicles. When used by itself, it usually refers to a motor home, most likely a Class A.

Condensation: The result of warm moisture-laden air contacting cold window glass. Keeping a roof vent open helps to reduce the humidity levels.

Converter: A device that converts 120 volt A/C (alternating current) to 12 volt DC (direct current). RV devices mostly run on 12 volt DC power that is supplied by the battery, which allows the RV to function independently. When “shore power” (an electrical supply) is available, the converter changes the voltage from 120 to 12 volt to supply the appliances and to recharge the battery.

Curb Weight or Net Weight: Curb Weight is the actual weight of a vehicle or trailer, including all standard equipment, full fuel tanks, full freshwater tanks, full propane bottles, and all other equipment fluids, but before taking on any persons or personal cargo.

Dinette: A booth-like dining area in which the table may be lowered to convert into a bed.

Diesel Pusher: See Pusher

Dinghy: See Toad

Direct Spark Ignition: A feature of new propane appliances whereby the gas is ignited by an electrical spark and monitored electronically.

Dry Camping: Camping in an RV without external water or sewer hookups.

Dry Weight: Dry Weight is the actual weight of a vehicle or trailer containing standard equipment without fuel, fluids, cargo, passengers, or optional equipment.

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 on the floor.

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.

Dual Rear Wheels: A truck having two wheels on each side of the rear axle for a total of four wheels.

Dump Station: Facilities for emptying gray and black water from the RV holding tanks.

Engine Oil Cooler: A heat exchanger, similar to a small radiator, through which engine oil passes and is cooled by airflow.

Exhaust Brake: A device installed on the engine which causes deceleration by restricting the exhaust gases. Exhaust brakes are used to supplement the service brakes of a vehicle and to increase stopping power. Especially useful to slow heavy loads down steep grades.

Exhaust Temperature Gauge (ETG): Gauge indicating engine exhaust gas temperature as measured by a probe inserted into the gas flow. Temperature is generally measured directly after the exhaust manifold or after the turbo. Useful in preventing engine overheating.

Fan Switch: A normally open switch that closes at a preset temperature. It causes the furnace to run for a short time after the thermostat opens, allowing the furnace to cool down.

Fifth-Wheel Trailers: Designed to be coupled to a special hitch that is mounted over the rear axle in the bed of a pickup truck. These trailers can have one, two or three axles and are the largest type of trailer built. Because of their special hitch requirements, fifth-wheel trailers can only be towed by trucks or specialized vehicles prepared for fifth-wheel trailer compatibility.

Furnace Ignition Control Board: When powered, initiates gas valve opening and spark sequence, which lasts approximately seven seconds. Newer boards are three tries (i.e., will attempt to ignite three times at approximately 60-second intervals). Older models are a single try.

FHU: See Full Hookup

FMV: Abbreviation for Fair Market Value.

Fresh Water Tank: Tank for holding freshwater for drinking, cooking, and bathing while not connected to a city water supply.

Full Hookups: Refers to an RV site with water, electricity, and sewer at an RV site. Hookups may also include telephone and cable TV in some campgrounds.

Fulltimer: A person living full-time in an RV, having no other home.

Galley: The kitchen in an RV.

Gas Pusher: See Pusher

Gross Axle Weight (GAW): Gross Axle Weight (GAW) is the actual weight placed on a single axle.

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 have two axles (tandem axles), then the RV would have a Gross Vehicle Weight Rating (GVWR) of 7000 lbs.

Gross Combination Weight (GCW): is the actual weight of the fully-loaded tow vehicle plus the towed vehicle (trailer, car, boat, etc.), including all cargo, fluids, passengers, and optional equipment.

Gross Combination Weight Rating (GCWR): Maximum allowable combined weight of the tow vehicle and the trailer, according to the vehicle manufacturer; includes the weight of both vehicles plus all fuel, water, supplies, and passengers and should never exceed. 

Gross Trailer Weight (GTW): 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 Rating (GVWR): The manufacturer’s maximum load weight, in pounds, allowed for the vehicle and should never be exceeded. This rating includes the weight of the vehicle plus fuel, water, propane, supplies, and passengers.

Gross Trailer Weight (GTW): is the same as for Gross Vehicle Weight (GVW) when referring to a trailer.

Gross Vehicle Weight (GVW): is the actual weight of the fully-loaded vehicle or trailer, including all cargo, fluids, passengers, and optional equipment, as measured by a scale.

Generator: An engine-powered device fueled by gasoline or diesel fuel, and sometimes propane, for generating 120-volt AC power.

Gooseneck: A trailer and hitch configuration connected to the tow truck directly above the rear axle by way of a standard ball hitch in the truck bed and a vertical, slender arm on the front of the trailer. Gooseneck hitching is common on horse and utility trailers but rarely found on RVðs.

Gooseneck Adapter: A device that attaches to the fifth wheel trailer’s kingpin and extends down about two feet. It couples with a ball hitch mounted in the bed of a truck, enabling the fifth wheel to be towed like a gooseneck trailer. For additional details see Fifth Wheel Gooseneck Adapter.

Gooseneck Extender: See Gooseneck Adapter

Grade: The degree of inclination of a road. A grade of 6% or higher is considered steep.

Gray Tank: Holding tank connected to the sinks and shower, designed to hold wastewater until it can be dumped into a septic system.

Gray Water: Disposal of water from sinks and shower. In some units, this is held in a holding tank separate from black water. See also Gray Tank 

Hookups: Campground facilities for connecting an RV to 120-volt AC “shore power,” water, sewer, cable TV and telephone service.

Heat Exchanger: 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: 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.

Holding Tanks: Tanks that hold water. There are three different holding tanks on most RVs; freshwater tank, the gray water tank, and black water tank. The freshwater tank holds fresh water that can be stored for later use. The gray water tank holds the wastewater from the sinks and showers. The black water tank holds the waste from the toilet. Their capacity determines how long an RV can be used without hookups.

Hookups: Campground facilities for connecting an RV to 120-volt AC “shore power,” water, sewer, cable TV and telephone service.

Honey Wagon: Euphemism for the sewage pumping truck. Honey wagons are used to empty RV holding tanks in places where full hookups and dump stations are not available.

House Battery: One or more batteries in a recreational vehicle for operating the 12-volt lights, appliances, and systems. House batteries can be 12-volt units tied in parallel or pairs of 6-volt batteries tied in series (to double the voltage). The term house battery is of more significance in motor homes because they contain one or more other batteries for the operation of the engine, referred to as the chassis or starting batteries.

Inverter: A device that converts direct current (DC) to alternating current (AC) for powering AC equipment while the RV is not plugged into an AC source. Typical DC sources are batteries and solar panels.

Kilowatt: (kW): A measurement of electrical power; each kilowatt equals 1000 watts.

Igniter Electrode: Similar to a spark plug. There are two versions; a three probe (remote sense) and a two probe (local sense).

Jake Brake: See Exhaust Brake

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.

Landing Gears: See Leveling Jack

Landing Legs: See Leveling Jack

Leveling Jack: A jack lowered from the underside of trailers and motor homes for the purpose of leveling the vehicle. A leveling jack is designed to bear a significant portion of the RV’s weight, even lifting it off the ground on certain models.

Limit Switch: Furnace safety switch, a normally closed switch that opens if it gets too hot, opening turns off power to the gas valve and igniter board.

Liquefied Petroleum Gas (LPG): commonly written as “LP gas”. Two examples of LPG are propane and butane. LPG is heavier than air in gas form and about half the weight of water in liquid form. Propane fuels RV appliances, such as the stove and refrigerator.

Light Weight RV: RVs that are designed to be easily towed behind most Minivans, light-duty trucks and cars! The most common being a pop-up trailer.

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

MH: See Motor Home

Mini Motor Home: See Class C

MotorCoach: See Motor Home

Motor Home: A motor vehicle built on a truck or bus chassis and designed to serve as self-contained living quarters for recreational travel. Also commonly spelled as a motorhome.

MSRP: Manufacturer Suggested Retail Price

Net Carrying Capacity (NCC): or Payload Capacity is the maximum amount of persons, personal cargo, optional equipment, and Tongue or King Pin weight that can be added to an RV. The formula for NCC is GVWR – UVW. NCC differs slightly from the more widely used “payload” term, by including full freshwater and propane tank weights. The NCC label in an RV may not include the weight of dealer- or factory-installed options already on the vehicle.

Payload: Payload is a weight rating. It is the maximum weight that persons plus cargo should never exceed.

Pilot: A small standby flame 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.

Propane or LPG (Liquefied Petroleum Gas): Propane or 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.

Pressure Regulator: See Water Pressure Regulator

Pull-Through: A slot in an RV park with an entrance and an exit, designed to pull the RV in one end and out the other, without having to back up.

Pusher: Motor home with a rear-mounted engine. Most pushers are equipped with diesel engines, but some gas engine models are also available.

Pyro: See Exhaust Temperature Gauge

Roof Air Conditioning: Air conditioning unit mounted on the roof of an RV to cool the unit when it is parked. When moving, most RVs are cooled by air conditioning units which are components of the engine.

RV (Recreational Vehicle): A motorized or towable vehicle that combines transportation and temporary living accommodations for travel, recreation, and camping. RVs come in all shapes and sizes for any budget or need. They range from camping trailers costing a few thousand dollars to luxurious motorhomes with prices well into six figures. RVs refer to multiple RV and RVers refer to their owners.

Rear Differential: A set of gears found in the rear axle of vehicles, designed to distribute drive shaft power to the two wheels. It applies power to both wheels while allowing each to spin at different rates during cornering.

Rear End: See Rear Differential

Rear Gross Axle Weight (RGAW): Rear Gross Axle Weight is the actual weight placed on the rear axle.

Rear Gross Axle Weight Rating (RGAWR): is the maximum number that the GAW of the rear axle should never exceed.

Retarder: give you another way to slow down, lessen the need to use the brakes, and reduce brake wear. All retarders can be turned on or off by the driver. As with cruise control, retarders should never be used on wet, icy, or slippery roads.

Rig: Slang for an RV.

RV: See Recreational Vehicle

RVCG: Abbreviation for the RV Consumer Group organization.

Safety Chains: A set of chains that are attached to the trailer A-frame and connected to the tow vehicle while towing. Safety chains are intended to keep the trailer attached to the tow vehicle in the event of hitch failure, preventing the trailer from complete separation. They should be installed using an X-pattern (crisscrossed) so the coupler is held off the road in the event of a separation.

Self Contained: An RV that 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.

Shore Power: A boating term adopted by the RV community to mean an electrical power hookup supplied to the RV by a fixed, external source (not by a portable generator). A full hookup RV site has shore power.

Slide Out: A compartment added to an RV to increase interior space. It slides into the body during travel and slides out when parked.

Snowbird: A person who moves from cold weather to warm in an RV, generally staying a season.

Solar Panel: Device containing an array of solar cells that convert sunlight to electricity. Typically mounted on the roof of RV’s and used for charging the batteries.

Stabilizing Jack: A jack inserted under or lowered from trailers and motor homes for the purpose of stabilizing the vehicle. A stabilizing jack is not designed to bear a significant portion of the RV’s weight, only a small amount to reduce movement during occupancy. Stabilizing jacks are generally found toward the back of trailers, under the kingpin of fifth wheels, and under some slides.

Starting Battery: See Chassis Battery

Stinky Slinky: Slang for the sewer hose, constructed from a spiral wire covered with vinyl. One end attaches to the RV piping and the other into the local sewer dump facilities.

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.

Toad or Dinghy: A vehicle towed behind a motorhome, sometimes with two wheels on a special trailer called a tow dolly, but often with all four wheels on the ground. That which was “towed”.The recommended amount of Tongue Weight is 10%-15% of the GTW.

Tongue Weight (TW): The amount of weight imposed on the hitch when the trailer is coupled. Also referred to as “hitch weight”. Tongue weight for a travel trailer can be 10-15 percent of overall weight; fifth-wheel hitch weight is usually 18-20 percent of the overall weight.

Tow Bar: A device used for connecting a toad/dinghy vehicle to the motorhome when it’s towed with all four wheels on the ground.

Tow Dolly: A low, wheeled frame with a platform used for carrying heavy objects. Motorhome owners often use tow dollies to haul a car or SUV behind their RVs.

Trailer Brakes: Brakes that are built into the trailer axle systems and are activated either by electric impulse or by a surge mechanism. The overwhelming majority of RVs utilize electric trailer brakes that are actuated when the tow vehicle’s brakes are operated, or when a brake controller is manually activated. Surge brakes utilize a mechanism positioned at the coupler that detects when the tow vehicle is slowing or stopping and activates the trailer brakes via a hydraulic system.

Transmission Cooler: A heat exchanger similar to a small radiator through which automatic transmission fluid passes and is cooled by airflow.

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

Unloaded Vehicle Weight (UVW) or Dry Weight: is the weight of a vehicle as manufactured at the factory. It includes full engine and generator fuel tanks and fluids, if applicable. It does not include cargo, water, propane, or dealer-installed accessories. It may or may not include factory-installed options. Be aware that some manufacturers weigh each unit to determine UVW, while others provide only the average or estimated weight for each model.

Water Pressure Regulator: Device installed on water hose attached to city water to limit the water pressure entering the RV. Most regulators limit water pressure to 40 psi.

Wet Weight: The weight of the vehicle with the fuel, freshwater, and propane tanks full.

Wheelbase: Distance between centerlines 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: An RV having an external body width greater than 96 inches (8 feet). The most common wide-body widths are 100″ and 102″.

WiFi: See Wireless Internet

Winterize: The process of introducing non-toxic antifreeze into the water lines of an RV for winter storage to prevent freezing and line breaks. 

Yaw: Refers to the “fish-tailing” action of a 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”.