115 Volt System

The main electrical source from the local municipality. Also referred to as 110 volt, 120 volt, or mains electric. 

120 AC/12 DC/LP Gas

120 AC is 120 volt alternating current (as in houses); 12 DC is 12 volt direct current (as in motor vehicles); LP gas is liquified petroleum gas or propane. Some RV refrigerators can operate on two of the three sources, others on all three. 


Absorption Term: Refrigerator

A refrigerator that uses heat instead of a compressor to circulate the refrigerant. Because there are no moving parts and the circulation of the coolant is dependent on gravity, the RV must be parked on a level surface for optimum functioning. 


A structure consisting of three walls that can be attached to an RV awning to create an additional room. They are sometimes available in hard-walled versions called “Florida rooms.”

Arctic Package

An RV that has been equipped with extra insulation and heat pads for holding tanks during winter time use.


The canvas or aluminum shade which is mounted on an RV. They may be automatic, in which case the awning is installed on a spring-loaded roll-up, or they may be manually propped up by a pole.

Axle Ratio

The ratio between pinion and ring gears in the differential that multiply the torque provided by the engine. It describes the number of driveline revolutions required to turn the axle once. With a 4.10:1 axle, the driveline turns 4.1 times for each axle revolution. Higher ratios mean more torque and more towing power, but less road speed for a given engine speed. In other words, a 4.10:1 ratio provides more torque than a 3.73:1 ratio.


Back-Up Monitor

Video camera mounted on the rear of the motorhome to visually assist the driver with backing up the motorhome via a monitor mounted in the driver’s compartment, or in the central area of the cab where it can be viewed by the driver from the driver’s seat. These monitors are usually left in the “on” position in order to also assist the driver with gauging the flow of traffic behind the motorhome, and in watching a towed vehicle. 

Ball Mount

The portion of the trailer hitch which holds the hitch, ball, and the connecting device for the sway bars on a weight-distributing hitch, and the ball alone on a weight-carrying hitch.


Refers to a storage area accessible from the outside, usually from the door threshold area down.


The auxiliary battery installed in some RV units to provide 12 volt lighting when the tow vehicle is not connected. When installed with an automatic charging solenoid, it charges through the tow vehicle alternator system, assuming the tow vehicle is wired with a charge line.

Black Water Tank

The holding tank under an RV used for storing sewage effluent. Sink and shower water is held separately in a gray water tank when a vehicle has a two tank system.


Camping outside a campground, usually for free, and relying on onboard 12 volt DC power systems for energy.

Breakaway Switch

A 12 volt switch in the trailer’s electric brake system that is tripped by a cable connecting the trailer to the tow vehicle. If the trailer should become detached accidentally, the cable pulls a pin out of the switch, causing the brakes to activate.

British Thermal Unit (BTU)

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

Bubble level

A device used to indicate the level of a trailer or motorhome. The level can be round or cylindrical. A round level should be placed on a flat surface that is meant to be parallel to the ground. Cylindrical levels are placed in pairs, one at the front of the trailer, and one on the side, in order to indicate the state of level from side to side, and from front to back.


The component in every LP gas appliance where the air and gas mixture ignites.



The portion of a Class C motorhome which overhangs the driver and navigator seats.


A group of three or more RVs travelling together.

Chassis Electrical System

Brake lights, turning signals, and running lights powered by the RV’s 12 volt system.

City Water Hook-Up

A water inlet that is provided for campground hook-ups, which bypass the RV pump and the water tank entirely. The pressure of the local water supply pumps the water through the RV plumbing system when taps are opened.

Class A Motorhomes

Commonly referred to as conventional motorhomes, they are the largest, and most luxurious of the motorized RVs, and consequently, the most favoured RV of full-timers. The Class A motorhome is entirely constructed on a specially designed motor vehicle chassis.

Class B Motorhomes

Commonly referred to as van campers, the Class B motorhome is a compact unit made from a cargo van, customized to include sleeping, eating, and bathroom facilities. They are popular because they can often be parked in family garages, used to tow a boat, or driven as a second vehicle.

Class C Motorhomes

Sometimes referred to as a mini-motorhome, the Class C is a scaled-down version of a larger motorhome, at a lower price. The Class C is built on an automotive-manufactured van frame with an attached cab. The motorhome manufacturer builds the living section onto a “cutaway” cab chassis.


The protective casing which partially surrounds the valve on an LP gas tank.


A device for changing 120 volt AC into 12 volt DC electrical power. Most RVs with electrical hook-ups will have a converter because many of the lights and some other accessories run on 12 volt DC power. 


Deep Cell / Deep Cycle Battery

A battery used exclusively by the living area of an RV, and not to start the vehicle. The more deep cycle batteries, the greater the longevity of your onboard power. The batteries are charged as you drive (if the tow vehicle is equipped with a charge line), when you are hooked up to 120 volt power (if the RV is equipped with a charger), by a generator, or by solar power. 

Demand Water System

The system activated when you open a faucet in the RV. As water pressure in the pipe falls, a switch turns on a pump which operates until the depleted pressure is restored. 

Diesel Pusher

A diesel-powered motorhome with a rear engine. 


A pickup truck, or light-duty tow vehicle, with four wheels/tires on one rear axle. Note: truck campers would need swing out brackets to clear dual wheels. 

Dump Station

The hole in which RVers can unload their black and gray water using a flexible hose attached to their vehicles’ holding tanks. 


Electric Brakes

The trailer brakes which are activated when the tow vehicle brakes are applied. An electric brake controller synchronizes the braking of the tow vehicle with that of the trailer. A hand control also allows the driver to apply trailer brakes independently. 

Electrical System

There are generally at least two electrical systems in RVs, namely the 12 volt, and the 110 volt. The systems are controlled through a power converter which switches from the 12 volt travelling system to the 110 volt campsite system. Some vehicles have a generator which feeds the 110 volt system; others have auxiliary batteries which feed the 12 volt system. 

Equalizing Hitch

A load-distributing hitch system which uses leverage to distribute the tongue weight of a travel trailer between the front and rear wheels of the tow vehicle. 


Fifth Wheel

A platform hitch that fits into the bed of a pickup truck. This platform on farm equipment originally looked like a wheel, and is where the fifth wheel unit gets its name. 

Fifth Wheel Trailers

Trailers designed to be affixed and towed by a pickup equipped with a special hitch in the truck bed. These are much like travel trailers, except they are built with a raised section that extends forward over the tow vehicle, making for a two-level floor plan. They are the largest of the towable trailers. 


Fiberglass sheeting used in RVs with fiberglass sidewall construction. 

Florida Room

The enclosed room created when walls are added to an awning. 

Folding Camping Trailers

A lightweight RV unit with sides, usually made of canvas, that collapse for towing and storage. They are also known as pop-up trailers. These are the smallest of the RVs that do not have an engine, and are easy to tow. The camping trailer combines the experience of tent camping with the comforts found in other RVs. When set up, they provide kitchen, dining and sleeping facilities for up to eight people. 

Fresh Water Hook-Up

One of two filling ports which feeds the fresh water system of the RV. One port has a hose connecting the RV to the water hookup; the other port is used as a funnel to fill the water tank for travelling. 



The built-in couch in an RV that converts into a bed. It often conceals storage compartments. 

Gear Vendor

Brand name for an auxiliary transmission designed to give the driver control of the vehicle’s gear ratio. It enables splitting gears for peak performance, and at the same time, allows for an overdrive. 


An electrical device powered by gasoline, diesel, or sometimes propane, for generating 120 volt AC power. 

Gray Water Tank

The holding tank that collects water from the sink and shower. It is one of two tanks in a two-tank holding system. 

Gross Axle Weight Rating (GAWR)

The maximum allowable weight, in pounds, each axle is designed to carry, as measured at the tires, therefore including the weight of the axle assembly itself. GAWR is established by considering the ratio of each of its components (tires, wheels, springs, axle) and rating the axle on its weakest link. The GAWR assumes that the load is equal on each side. 

Gross Combined Weight Rating (GCWR)

The maximum allowable combined weight, in pounds, of the tow vehicle and the attached towed vehicle. GCWR assumes both vehicles have functioning brakes, with exceptions in some cases for very light towed vehicles, normally less than 1,500 pounds (check your chassis manual or towing guide). 

Gross Vehicle Weight Rating (GVWR)

The maximum allowable weight, in pounds, of the fully loaded vehicle, including liquids, passengers, cargo, and tongue weight of any towed vehicle. 


Hitch Weight

The amount of a trailer’s weight that rests on the tow vehicle’s hitch. The hitch weight should be 10-15% of the total weight of the trailer for conventional trailers, and 15-20% for fifth-wheels. 


The restless feeling that sometimes afflicts RVers after staying too long in one place. It requires that they hit the highway once again. 


The steel ball attached to the towing vehicle that connects with the travel trailer. 

Holding Tank

There are three different holding tanks on most RVs: the fresh water tank, the gray water tank, and the black water tank. The fresh water tank stores fresh water for later use. The gray water tank holds the gray water from the sink and shower. The black water tank holds the black water, or sewage effluent from the toilet. The capacities of the holding tanks determine how long an RV can be used without hook-ups. 


The water, sewer, or electrical connections that are provided at campsites, often referred to as “three-way hook-ups”. Hook-ups may also refer to campground facilities for cable TV, and telephone service. 



A device for changing 12 volt DC into 120 volt AC power. 



A sandwich of structural members, wall paneling, insulation, and exterior covering, bonded under pressure and/or heat, in order to form the walls, floor, or roof of an RV. 

Leveling Jack

One of four lifting systems located at each corner of the RV to provide a solid and level foundation. 

Liquefied Petroleum Gas

Also referred to as LP gas, or propane. LP gas consists of flammable hydrocarbons and is obtained as a by-product from the refining of petroleum or natural gas. It is transported in liquid form under pressure, and vaporizes in the fuel tank. Propane fuels RV appliances such as the stove, water heater, and refrigerator.


The 1/8” backing board for filon (the fibreglass sheeting used in RVs with fiberglass construction). Luan is the base that the filon (fibreglass) is glued onto. 


Monitor Panel

A visual indicator of fluid levels within the storage tanks of the RV. 


A recreational camping and travel vehicle built on, or as part of, a motorized vehicle chassis. The three basic types are Class A, Class B, and Class C. 


Net Carrying Capacity (NCC) Or Payload Capacity

The maximum weight of all personal belongings, occupants, food, fresh water, LP gas, tools, dealer installed accessories, etc., that can be carried by the RV. Technically, the GVWR less the UVW equals the NCC. 



Abbreviation for “original equipment manufacturer.” 


Pilot Flame

The heat source which ignites LP gas in the RV appliance system. The pilot flame heats the thermocouple control, permitting the flow of gas to the burner. 

Pilot Safety Button

A manual control on LP gas appliances that, when activated, will bypass the thermocouple to allow the appliance pilot to be lit. If this bypass button is not pressed when lighting the pilot, the thermocouple stops the flow of gas to the appliance, in order to prevent LP gas from being released into an appliance in which the pilot has gone out. 

POL Connection

A fitting which is screwed directly into the valve of the LP gas tank, between the tank and the regulator. 

Portable Toilet

An RV toilet with a built-in water tank and holding tank. When the holding tank is full, it may be detached and taken to a dump station. 

Power Converter

The electronic circuit panel which switches from 110V to 12V when the RV is hooked up to the mains electric supply. It also houses the fuse and circuit breaker panel. 


Refers to rare RV campsites that allow vehicles to drive straight in and hook up without having to back in. 



The LP valve controlling the gas flow through all appliances, and maintaining the appropriate pressure in the LP gas system. 

Relief Valve

A safety release in RV systems which opens when the temperature or pressure exceeds set limits. They are found on LP gas systems, and on pressurized water systems. 


Nickname for a whole family of recreational vehicles that combine transportation and living quarters for recreation, camping, and travel. They can be divided into three general categories: those that have power trains (motorhomes), those that are towed behind a tow vehicle (trailers), and those that are carried (campers). 


Screen Room

Term for screen enclosure that attaches to the exterior of an RV for a bug-free, outside sitting area. Some screen rooms have a canvas roof for rain protection as well. 

Septic Tank

The black water holding tank. 

Shore Power

Electricity provided by an external plug to an external power source. 


The Slabs is a nickname for Slab City, an old military base in the desert along the Salton Sea in Southern California. Camping is free, and thousands of RVers visit Slab City every winter. 


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


Additional living space that slides out, either by hydraulics, electricity or manually, when the RV is set up for camping. 


An RVer who follows the sun south during the winter months.

Stabilizing Jack

A set of two or four are used to stabilize the RV once it is level. 

Surge Brakes

A hydraulically-operated braking system used on some lightweight trailers. Pressure against the hitchball activates the brake system, eliminating the need for electrical brake controls. 

Sway Bar

A device connected from the A-frame of the trailer to the hitchball platform of the tow vehicle in order to reduce sway. 



The heat-activated shutoff valve that prevents LP gas from flowing to a pilot that has gone out. 

Three-Way Refrigerator

A model which runs on 12 volt, 115 volt, and LP gas sources. 


Term for the room (generally in older RVs) that “tipped-out” for additional living space once the RV was parked. Newer RVs mainly use slide-out rooms. 

Tongue jack

The lifting device which raises the trailer tongue hitch off of the hitchball. 

Torsion Bars

The steel bars in equalizing hitch systems used to lever a portion of the weight of a trailer’s hitch weight onto the forward axle of a tow vehicle. 

Toy Hauler

Term for fifth wheels, travel trailers, or motorhomes with built-in interior cargo space for motorcycles, bikes, etc.

Travel Trailer

A unit designed to be towed by a car, van, or pickup, by means of a bumper or frame hitch. They range in size from a small bedroom on wheels, to large and luxurious. Due to the weight of all but the smallest units, the tow vehicle must have a special load-distributing hitch. Like all towable units, they can be unhitched from the tow vehicle, which is then available for local travel use to and from the campsite. Travel trailers sleep four to eight people. 

Truck Campers

An RV unit loaded onto, or affixed to, the bed or chassis of a pickup truck. Usually the tailgate is removed and the camper unit is attached to the truck with frame-mounted tie-downs. Truck campers sleep two to six people. 



The RV’s underfloor surface protected by a weatherproofing material. 


Water (weight)

8.3 lbs. per gallon. 

Wet Weight

The weight of an RV with all storage and holding tanks full, i.e. water, propane, etc. 


The distance between the centre 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 centre point between the rear axles. 


An RV that has a width exceeding eight feet.

The main electrical source from the local municipality. Also referred to as 110 volt, 120 volt, or mains electric.