Like almost everything, RV-ing comes with its own jargon. Some terms can usually be figured out with a little thought while others seem to be from a foreign language.

-- Also called a "bus" or "pusher", the latter due to the fact that the engine is in the rear.

Term	Meaning
Apron	The length and width of parking area available to park an RV. Some aprons are long enough to hold a tow or towed vehicle; some are too short so that RV-ers have to park the other vehicle either alongside the apron or in some other area. Aprons are also called "parking pads", and may be made of dirt, gravel, grass or pavement.
Black water tank	The tank used to collect toilet refuse. Black water is kept in a separate tank from gray water. Black water tanks can be emptied at an on-site sewer disposal or at a dump station.
Blue boy	See "honey wagon".
Boondocking	Slang term for camping off-the-grid, without hookups like water, electric, cable or sewer. Also referred to as "gravel pit camping" or "dirt camping".
Bus	See "motorhome".
Converter	An electronic device used to convert 120 volt (alternating) current into 12 volt (direct) current. It is used to supply voltage to a rig's 12 volt fuse panel. Some converters also have chargers used to maintain charge on a rig's house battery.
DEF	Diesel exhaust fluid -- for school buses etc, some trucks need it.
DTV	DirecTV, a satellite TV provider, a competitor of Dish TV. Campers can get satellite reception either by using a ground mounted rooftop mounted dish. Some rooftop units are capable of locating necessary satellites on their own.
Dump station	A gray water and black water dump facility used to empty a rig's gray and black holding tanks. Dump stations are normally found at the exit of RV campgrounds.
Fifth-wheel	[TBD]
Gray water tank	The tank used to collect sink water from the kitchen and bath basins as well as the bath shower. Gray water is kept in a separate holding tank from black water. Gray water tanks can be emptied at an on-site sewer disposal or at a dump station.
Honey wagon	A septic pumper truck that comes around to your website to suck out your gray and black water tanks. Honey wagons are normally found at campgrounds that don't have on-site sewer. Sometimes referred to as "sewer suckers", their services can be fee-based or free. You may or may not have to be at your rig when the pumper comes around. The term also refers to a small container used to carry sewage from a rig to the dump station. BTW: If you're interested, the term comes from the old western expression for a wagon carrying dead bodies. Sometimes called a "blue boy".
House battery	The 12 volt battery contained in your rig, probably somewhere in the front. Unlike vehicle batteries, RV house batteries should be deep cycle batteries. Motorhomes have both house batteries and vehicle batteries.
Hookup	The water, electric, cable and/or sewer services offered by a campground. Not all campgrounds offer all of these services; those that have water, electric and sewer are sometimes called "full hookups". Electric can be any of 15/20 amp, 30 amp, 50 amp or some combination of these.
Inverter	An electronic device used to convert a battery's 12 volt (direct) current into 120 volt (alternating) current for powering things like a microwave oven, TV or maybe even an A/C.
Landing gear	The front "jacks" on a fifth-wheel trailer. Note that the term is somewhat of a misnomer because even they are used to raise the front of a trailer, they cannot be used to lift the trailer off the ground.
Motorhome
ODS	Abbreviation for Opposite Door Side. A reference to the side of a rig opposite the entryway doo; the "driver" side. You will occasionally see references to things like the ODS lights. I affectionately refer to this as the Other D**n Side.
Popup	A relatively small type of camping trailer that can be collapsed for easy storage or pulling. Popups can have side rooms for extended living area. While generally cheaper than other types of RV, some premium popups have amenities like a shower, toilet, slide-out, dinette, microwave and oven.
Pusher	See "motorhome".
Reefer fuel	A type of off-road diesel intended for farm equipment. Although it is available at truck stops, it should NOT be used for on-road vehicles like your tow vehicle or motorhome. See here for a discussion.
Shore power	The 120v electric hookup at a campground, house or building. Shore power is distinguished from 12v battery power or 120v supplied by a generator.
Slide-out	A "room" of an RV that can be extended outward to provide more room inside the rig. Some RVs have multiple slideouts; for example, one for the kitchen, one for the living room and one for the bedroom. Slideouts are normally operated by the rig's 12 volt house battery and come in several types: cable, screw or pneumatic, for example.
Stabilizers	Jacks on the rear (and center) of an RV used to help prevent lateral or vertical movement. Although the term "jack" is used, they are used for stabilization only and do not actually jack up the RV. Rear stabilizers are not the same thing as the front jacks (landing gear).
Toad	Slang for "towed", referring to a vehicle pulled behind a motorhome.
Tow vehicle	A truck or other type of towing vehicle used to tow a trailer. Fifth-wheels and other type of trailer rigs require a tow vehicle since they have no engine of their own. Motorhomes do not require tow vehicles, although they may in turn tow another vehicle like a jeep.
Toy hauler	A type of fifth-wheel trailer that has a separate room in the rear for carrying things like ATVs, motorcycles, small cars, Ski-Doos, kayaks or canoes, hot air balloons and other such goodies. Toy haulers have a separate large door at the rear for getting the toys in and out. Instead of using for those kinds of things, some folks use a toy hauler rig to provide a separate living area, a type of mother-in-law suite.
Tractor fuel	Diesel fuel used for on-road driving. The term is used at truck stops and is confusing because it refers to the type of cab used by big-rig semis, not farm tractors. If you're still confused, go inside and ask the cashier which one you should get. See here for a discussion.
Umbilical cord	The multi-wire electric cord that connects a tow vehicle to a trailer. The internal wires of the cord control turn signals, stop lights, brake lights and marker lights. There are also wires to operate the automatic brakes and to help maintain charge on the trailer battery.
Vehicle battery	The 12 volt battery contained in your tow vehicle or motorhome. Motorhomes have both house batteries and vehicle batteries.