The Definitive Automotive Dictionary

The Definitive Automotive Dictionary provided by Action Auto and Boat Donation Services:

Amorphous silicon – Used in a variety of electronics. A non-crystalline form of silicon that can be laid in thin layers of film to produce photovoltaic cells, it can be used on plastic substrates and metal.

Ampere-hour – A measurement of a unit of electrical charge of current, over a specific period of time, usually used to find the strength of a battery.

Amp/hr. rating – The measuring of current to determine the ability of a battery. The higher the amp, the stronger the battery

Amplifier – Used in auto radio systems, to produce a greater electrical signal, by increasing the electron flow in a vacuum or electric circuit.

Air Management Unit (AMU) – Located in a chassis cross-member and using the multiplex electrical system, it is pressure switches put together in such a way as to control the pneumatic accessory functions of a vehicle.

Back axle – The axle in the rear.

Back band – The soft member that cases a door or window.

Backbone network – The computer network that links lower capacity networks usually using fiber optics.

Backfire – The noise or explosion that occurs when unburned fuel enters the exhaust system and is ignited. This can also occur by a flame from a cylinder in the intake manifold when an intake valve leaks.

Back flushing – To force liquid in an opposing direction, as when cleaning an engine’s cooling system.

Backlight defogging system – A rear window that is heated.

Balanced crankshaft – A vibration damper that has extended reinforcements.

Cailletet's process – A process for liquefying gases based on free expansion from a higher to lower pressure.

Calendering – Inside the tire casing, it is a thin layer of rubber that protects the tube from chafing and the carcass cords from getting wet.

Caliper – Disc brakes device that clamps on around the rotating disc and presses the pads against the disc to slow or stop a vehicle.

Camber – An adjustment in the alignment of a wheel in an outward or inward tilt.

Camshaft drive sprocket – Attached to the crankshaft, it is a sprocket that drives the camshaft by way of a chain.

Capacitor – An electrical storage device used on some motors to run or start circuits.

Capillary – Used for temperature gauges, it is a tube with a very small bore.

Capping – The re-treading of a tire carcass.

Cap stat – An expandable thermostat (wax-type) located at the bottom of a SU carburetor that reduces fuel flow when the temperature rises under the hood.

Cap wrench – A tool that fits on to one end of an oil filter in order to install or remove the filter.

Carbon build-up – Burned oil that is deposited in the combustion chamber atop the piston and head, which can cause sticky valves and an inefficient engine.

Carbon filter – An activated carbon air filter used as a cleansing agent.

Damp – 1. The reduction of any vibration to the crankshaft. 2. To slow the oscillations in a carburetor piston, spring or other like items.

Dampening belt – The belt that is wrapped around the outside of the brake drum or rotor before it is machined, that help to hamper vibrations that can damage a finished surface.

Damper springs – To provide a cushion from sudden loads because of abrupt engagement using springs in a clutch plate.

Dashboard – The inner front area behind the steering column that contains the warning lights, switches, instrument panel, gauges and other driving instruments.

Dash-pot – An instrument called a diaphragm used to control the rate in which the throttle can close.

Day-night mirror – A mirror that is usually mounted on the windshield that has an adjustment to prevent the glare from the headlights of cars that are following behind.

Drive belt – A rubber belt that is used to connect engine parts such as the alternator, power steering pump, water pump, etc.

Easing fluid – Penetrating oil

Factory adjusted – Part of a vehicle that has been set or established by the manufacturer and is not meant to be adjusted or changed.

Fader – Referring to the front and back speakers, a device that adjusts the balance of sound.

False air – An unmeasured air leak into the intake system between the intake valves and the airflow meter making the reading false.

Fan – A fan has 4 to 6 rounded curved blades that quickly rotate in order to help cool an engine; usually located by the radiator where it can pull air through the radiator. Fans are also used to push air throughout the inside of the vehicle for heating and cooling.

Fan pulley – Located on the hub of the radiator fan, it is the pulley on which the driving belt runs.

Fast idle – The opening of the throttle by way of engaging the choke in order to make the engine run faster so as not to stall.

Fatigue corrosion – An atmospheric condition that causes corrosion through repeated stress.

Fault reader – An electronic device that through a vehicle’s diagnostic system can provide a read out of possible issues with components.

Gap bridging – Carbon deposits that form between and across the spark plugs that can short out a plug.

Gap style – The way in which spark plug electrodes are arranged.

Gas cap – The vented cover that is twisted or snapped into place over a gasoline chamber’s entrance.

Gas damper – A shock absorber for gas.

Gas fade – Hot gases and dust that cause brake fade due to a reduction in friction between the drum and brake linings after hard braking.

Gas filter – A fiber device that screens impurities from gasoline.

Gas gauge – Located on the dashboard, a gas gauge is either a digital reader or fluctuating needle that indicates how many gallons of fuel are left in a fuel tank.

Gasket – Made from cardboard, paper, rubber, soft metal or asbestos, a gasket is a material that is used to insure a good seal between two metal parts.

Gas pedal – An accelerator device that increases the amount of fuel to the engine by pushing down on the device with one’s foot.

Gas tank – The metal container that is used to store fuel.

Half shaft – The two turning shafts, which connect the wheels to the final drive in a rear suspension or front-wheel drive.

Halogen bulb – A brighter light that contains a trace of a halogen like iodine.

Jack – A device often stored within a vehicle that allows one to lift a portion of a vehicle in order to repair it or change a tire.

Jamb switch – A button that is located in a doorjamb that is pushed in when the door is closed and pops out when the door is opened to switch on courtesy lighting within a vehicle.

Lagging – Using a non-conducting material to cover hot fluid lines so that the temperature can be maintained.

Laminated windshield – The process of adding a thin layer of plastic lining between two-layers of tempered glass so that if shattered it will not splinter apart.

Magnetic gasket – A material used to seal a door tightly closed using magnets that are inserted into the gasket.

Mag wheel – Wheels made of magnesium, aluminum or a combination of steel and aluminum making them lightweight.

Nave plate – The hubcap

Oil pan – An area that is bolted to the bottom of the crankcase that holds engine oil and keeps foreign bodies like dirt out of the engine.

Pad – A term often used to describe the brake shoe in disc brakes.

Radial cooling fins – Parallel to the centerline of the axle are brake drum cooling fins.

Radiant heating – When hot surfaces radiate heat into a space to make it warm or hot.

Safety belt – A belt worn by passengers in a vehicle to keep them in place in case of an accident or quick stop.

Tachograph – A gauge that registers vehicles miles, speed, distance, and other trip information often used in commercial transport vehicles.

Tailgate – A latching fold down side of a truck bed found in the rear - can also be part of a SUV or station wagon or other similar vehicle.

Vacuum activators – Used in air conditioning systems, a system of valves and dampers controlled by the vacuum from the engine intake manifold.

Valet switch – A toggle or button that overrides the alarm system when an automobile is being valet parked or for other services.

Water-cooling system – Used on most vehicles, it is a cooling system that runs water around the cylinders to keep the engine from overheating.

Window regulator – Is either a manual or electric mechanism to raise or lower a glass window.

Wrist pin – Passed through the piston, it is a round pin made of steel that is used as a base to fasten the upper end of the connecting rod.

X-valve – Either an intake valve that allow oxygen and fuel to go to the cylinder head or an exhaust valve that allows the already used gas to exit.

Y-connector – A line shaped in a Y as with a windshield washer pump connection to the spray nozzles.

Yoke – A yoke may be used on the forked sections of a U-joint or in a center pull braking system it is a triangle shaped piece of metal that connects the main brake cable with the stirrup cable.

Zigzag spring – The wavy type springs used in creating bases for the construction of seats.

Zero governors – Devices that regulate in adjusted forms, the delivery of gas within its flow rating at atmospheric pressure.

Dictionary of Automotive Terms

Auto Trader

Car Donations

British and American terms

Mobil Oil glossary of terms

Engineering Dictionary

Dictionary of Historic Automotive Terms

Canadian Automotive Terms

English/Spanish glossary

The Auto Glossary