AUTOMOTIVE GLOSSARY

(September 2024)

We are inundated with the special terminology found in the world of vehicles through everyday conversations, automobile commercials, repair shops, claims, vehicle rental and in many other situations. However, familiarity via hearing or seeing a word or phrase is often not the same as understanding the term. Just for your reference, we offer the following definitions of a few of the most common words and phrases. The information will not transform anyone into an automotive expert, but it should help your understanding.

A

a-arm–A wishbone-shaped suspension linkage found in the front of a vehicle’s chassis. It permits freer movement of wheels.

A-pillar–The car roof supports that frame a vehicle’s windshield.

ABC–See aerial bunched conductors.

abrasion resistance–Refers to wire insulation material resistance to mechanical wear to its surface.

a/c–Air conditioning.

active safety features–Refers to features that interact with, or are controlled by, the drive such brakes, anti-lock braking system, manual seat belts, suspension system and traction control.

active suspension–A system of actuators (instead of shocks and springs) which, via computer, controls wheel movement and positioning.

adaptive headlights–Front lights designed to move in concert with vehicle steering which enhances road visibility.

Advanced Driver Assistance Systems–Umbrella reference to all vehicle equipment designed to monitor and mitigate hazardous driving situations, including alerts to the operator. Examples are lane departure alarms, distance sensors and automatic brakes.

aeration test burner–A method for evaluating commercial gas combustion.

aerial bunched conductors–Refers to a bundle of three twisted wires that are used in vehicle transmission.

aerodynamic– Any situation involving a design that allows for efficient airflow.

a-frame–See a-arm.

after-market parts–Auto parts made by companies other than the original equipment manufacturer (OEM) and which are used for replacing or repairing autos. After-market parts are generally less expensive than OEM parts. It’s often alleged that such parts are inferior in quality compared to OEM parts.

air bag–It describes a gas-inflated cushion that deploys at the time of impact and is designed to protect a person’s upper body from making direct contact with a vehicle’s interior components such as the steering column or dashboard; rear-seat as well as side air bags are also becoming options.

air dam–Spoiler located beneath vehicle’s front bumper to increase radiator cooling and reduce drag normally caused by airflow between the vehicle and road surface.

air filtration system–System that cleans smog, pollen, exhaust, smoke, and odors out of the air. Cleans both interior circulated air and that coming from the outside.

anc–Means at no extra cost.

anti-dive–Front-end suspension feature that reduces a car’s tendency to be forced downward (dive) during braking.

anti-lock brake system (ABS)–A braking system that is designed to preserve the driver’s ability to steer a car during an emergency braking situation; unlike conventional brakes which lock and steering control is lost.

anti-roll bar–A suspension component that equalizes vertical movement among a pair of wheels in order to reduce the chance of a vehicle rolling.

anti-squat–Rear-end suspension feature that reduces a car’s tendency to be forced downward (squat) during aggressive acceleration.

automatic safety features–Refers to features that are not under a driver's control; rather they act in response to programmed circumstances. For example, air bags and automatic seat harnesses.

automatic transmission–A transmission where the gears are shifted automatically by the vehicle and controlled by a torque converter. The torque converter replaces the clutch. It connects and disconnects the engine from the drive wheels while selecting the proper gears for the speed of the car. These transmissions come in three, four and five speeds. The more gears involved, the smoother the acceleration. With four and five speed transmissions, the highest gear is for overdrive. Overdrive reduces the revolutions per minute (RPM) and provides better gas mileage while on the highway.

Automotive Service Excellence (ASE)–Refers to the National Institute for Automotive Service Excellence. The institution is an independent organization that tests and certifies automotive technicians.

autonomous vehicle–Vehicles equipped to operate in traffic without need for human driver. Such vehicles are programmed with operating instructions, traffic protocols, safety systems and satellite tracking that enables site-to-site travel.

AV–See autonomous vehicle.

B

B+–An acronym that refers to a battery’s positive voltage.

B-pillar–The car roof support located between a vehicle’s front and rear windows.

babbitt–A metal alloy that is highly resistive to friction. It is composed of antimony, copper, and tin.

back axle assembly–See rear axle assembly.

backbone frame–A box-like form located centrally in a vehicle to which the front and rear suspensions are attached.

backfire/backfiring–When fuel that hasn't been burned seeps into the exhaust system and is ignited, causing a small explosion.

backflushing–Pushing fluid in the reverse of its normal direction to clean an engine cooling system.

back-kick–An engine’s violent, reverse motion that is caused by a backfire.

backlight defogging system–A heated rear window.

balance shaft–A rotating shaft, placed in pairs in an engine to help reduce engine vibration, creating a smoother ride.

battery electric vehicle–See electric vehicle.

beam axle–An axle (rigid, thick metal rod) that connects and supports non-powered wheels.

beltline–Refers to the border of the bottom edges of a vehicle’s windshields and windows.

bevel gears–A gear set consisting of cone-shaped gears which allows for greater operating efficiency.

biodiesel–A blended mixture of petroleum and vegetable oil/animal fat fuel.

blind spot monitoring–A device that surveils the rear areas of a vehicle and alerts drivers when another vehicle is in those spots that are difficult for drivers to sport via mirrors.

block–Short for engine block; see the definition of crankcase.

brake bias–How a vehicle’s braking system’s power is distributed so that the possibility of locked brakes is minimized.

brake torquing–Firm, consistent braking with the left foot combined with aggressive use of throttle to create a powerful, turbocharged start as brakes are suddenly released.

breathing–Refers to an engine's capacity to circulate the air/fuel mixture (including exhausts) and it is related to an engine’s power generation.

bushing–Metal bearings with a certain level of rotary motion. They are components of a vehicle’s suspension system.

C

C31–A computer that monitors and adjusts a vehicle’s coil-ignition system.

Cabriolet–European term for convertible vehicle.

cam–Part of the mechanism that opens and closes the valves.

cam profile–The shape of cam openings that regulate how long a valve remains open.

camshaft–Shaft (rod) fitted with a system of cams that convert rotary into linear motion.

carburetor–The fuel system component that supplies the proper mixture of fuel and air to the engine. This part of the engine also adjusts the air and fuel mixture within an engine to meet different operating conditions (e.g., heat or altitude).

car types–The basic types of automobiles marketed to the general public. See the definitions for convertibles, coupes, hatchbacks, mini-vans, pick-ups, sedans, sports, sport utility vehicles, station wagons.

catalytic converter–A part of an exhaust system that reduces harmful emissions caused by the engine. This device became a standard feature in 1975 as an anti-pollution measure.

CCA–See cold cranking amps.

center differential–See rear axle assembly.

chassis–Once this was simply defined as the frame of the car which provided the strength of the vehicle, and to which the body, engine, drive line components and suspension were attached. Now, few vehicles other than trucks have separate frames, and the chassis structure is incorporated into the body components in what is known as a shell or unit body construction.

cold cranking amps–The vehicle battery power that’s available to start an engine under cold conditions.

combustion chamber–The cylinder of space that is traveled by a piston in which air and fuel are mixed and ignited in order to power a vehicle engine.

compliance–Bushings that adjust slightly to soften the impact when tires hit bumps.

connecting rod–Rod that attaches a piston to a crankshaft.

convertible–Describes any car with a top that can be lowered or removed. Such tops may be moved either manually or automatically and, typically, are made of canvas with a plastic rear window.

cornering limit–Refers to the top speed that a given vehicle can safely negotiate a turn.

coupe–A four-door passenger car with a separate trunk which is similar to a sedan but, instead of full-sized, the rear doors are cut (or in French, coupe) in order to allow a more stylish body.

crankcase–Engines consist of three major elements: the cylinders in which the pistons move; the cylinder head where the fuel/air combination enters, where combustion occurs, and where the burned gasses are vented off; and the crankcase which houses the crankshaft and usually the oil supply. The crankcase is usually the major (largest) part of the engine and is also referred to as the (engine) block.

crankshaft–The rod that is connected to engine pistons to assist with the conversion of piston (vertical) motion into rotary motion.

crumple zone–The areas of the vehicle outside of the passenger compartment that are designed to absorb the impact during a collision.

curb weight–Vehicle weight that includes full fuel tank without cargo or passengers.

cylinder–A chamber within an engine which contains a piston and valves. A fuel and air mixture in the cylinder is compressed by the piston and then ignited. This controlled explosion moves the piston, creating the basic force of the engine (power).

D

dashboard–The panel located just beneath a vehicle’s windshield where the various gauges, indicators, sound system and steering column are mounted.

Note: The dashboard was first installed in the front of carriages so that the dirt, mud, stones, and other objects kicked up from the road would be dashed against the bottom of the board rather than upon the riders.

daytime running lights–Front lights that remain lit during the day to enhance the ability of other drivers to see a vehicle.

dead axle–See beam axle.

dead pedal–A footrest located on the far left of the floor which is used as bracing during hard turns.

detailing–Merely an upscale term for cleaning a vehicle, usually in reference to a very thorough cleaning of either the interior or exterior that results in a "like new" condition and is generally done by specialists.

detonation–See knock.

differential–See rear axle assembly.

disc brake–A brake that works by a caliper squeezing two friction pads against a disc that is attached to a car’s wheel. This braking system is becoming dominant over the older, less efficient drum brake.

drive line–The components that make up a drive train with the exception of engine and transmission.

drive shaft–A long, metallic tube that connects the transmission and the rear axle.

drive train–The vehicle components that creates and distributes an engine’s power to a vehicle’s wheels (it includes the transmission).

drivability–Subjective measurement of a vehicle’s driving operation, including steering response, idling, braking, acceleration and climbing.

drum brake–A brake that works by curved brake “shoes” pressing against the inside of an iron drum that is attached to the wheel.

dubs–A slang term for wide (at least 20 inch), custom tires.

E

electric vehicle–A vehicle that is powered by a large, self-contained battery instead of an internal combustion engine.

electronic brake force distribution–A system that controls braking among the front and rear vehicle tires in order to improve stopping ability.

electronic transmission–A computer-controlled automatic transmission which has four forward gears, and one reverse gear. One does not have to manually shift the gears.

EGR–See exhaust gas recirculation.

engine–A power plant that uses the force of exploding fuel (typically gas, diesel fuel, alcohol, or propane) to create a rotating action to drive the car's wheels. The engine is usually made of pistons linked to a crankshaft to create this rotating motion or may involve a Wankel rotary engine which uses a rotating piston.

engine-control system–Refers to an automated system that monitors and controls critical parts of engine operation.

engine displacement–The total displacement of an engine that is usually expressed in either liters or cubic inches. This is the total volume within an engine devoted to the combustion which produces power.

Environmental Protection Agency (EPA)–Federal agency that oversees commercial operations that affect the United States’ natural resources. The EPA establishes and enforces vehicle fuel efficiency standards for the auto industry.

EREV–Stands for extended range electric vehicle.

exhaust gas recirculation–The process of sending back part of a vehicle’s exhaust into a manifold which absorbs heat and reduces the production of nitrogen oxides.

exhaust manifold–The vehicle network that processes and distributes exhaust (spent air-fuel mixture) gases.

F

fabric cord–Material used in vehicle belts and tires.

factory specs–Refers to a vehicle manufacturer’s parts clearances, dimensions, and tolerances.

feedback fuel-air ration control–Computer system that uses sensors to regulate the optimum mixture of fuel and air for vehicle’s ignition system.

floorpan–A vehicle’s largest metal stamping which becomes its floor and which primarily determines its structure and where many components are affixed.

four-wheel drift–Loss of traction of all four tires during cornering.

four-wheel drive–When the engine supplies power to all four wheels for the purpose of greater tire traction. The option may be full-time, but there is usually an option to switch from two-wheel to four-wheel drive.

four-wheel steering–A steering system exerts actual guidance to all four of a vehicle’s wheels rather than just the two, non-powered wheels.

front axle assembly–See rear axle assembly.

front wheel drive–When the engine supplies power only to the front wheels of a vehicle. This option is usually restricted to smaller vehicles.

fuel injection–Fuel injection is an electronic system that increases performance and fuel economy because it monitors engine conditions and provides the correct air/fuel mixture based on the engine's demand. Fuel injection injects the fuel directly into the cylinder head enabling more precise control over the quantity used. Eliminates the need for a carburetor and the complex, imprecise tuning that goes with it.

G

G–A measurement of lateral acceleration force. A single g equals the force caused by moving slightly more than 32 feet per second at sea level.

GA–Short for Gauge.

gallery–Engine tubing designed to transfer fluids and gases.

gap–See spark plug gap.

gear–Circular, metal, tooth-edged parts that engage with other such parts in order to transfer/transmit engine power.

gear oil–Lubricant designed especially for enhancing the operation of a vehicle’s transmission gears.

gearset–Any two or more gears that distribute vehicular power.

gray market–Refers to cars that are bought in a foreign market and shipped to another market to avoid import inspections. This market is used for getting cars at discount prices, but buyers typically have problems getting the cars serviced by dealers, particularly warranty work.

greenhouse–Part of car body that exists above the vehicle’s beltline.

group number–An ID number that appears on vehicle batteries which represents different characteristics including it place of manufacture and its physical dimensions.

H

half-shaft–A shaft that is a component within an independent suspension system that distributes power between differentials and wheels.

hatchback–A two- or four-door car with either a coupe or sedan styling but with a door (sometimes referred to as a third or fifth door) in its back instead of a trunk. The backseats in hatchbacks generally fold down for extra cargo space.

hemi–An engine that is fitted with hemispherical combustion chambers which consist of large, paired valves that substantially increases it capacity to gather air.

high intensity discharge headlights–A type of car light that uses electricity infused gases to create an intensely bright, white light.

horsepower–One of several measures of engine power. In this instance, an engine’s ability to move a vehicle. The higher the horsepower of the vehicle, the more mass it can move; in other words, it’s more powerful.

hydraulic brakes–Brakes that use pressurized fluid instead of a cable. When the brake pedal is pressed, hydraulic fluid forces the pistons to put pressure on the brake pads which rub against the brake disc and cause enough friction to stop the vehicle.

Hybrid electric vehicle–A car containing a self-contained rechargeable battery that assists the engine to propel it.

hydraulic fluid–A fluid that is under pressure in a system. In cars, hydraulic fluid systems replaced wire and rod systems to perform steering and braking more reliably and efficiently.

I

ignition system–The electrical system that produces a spark to ignite the fuel/air mixture in a gasoline engine.

independent suspension–Wheel suspension that operates separately from any other wheel, which improves vehicle handling and performance.

intake charge–The mixture of air and fuel that flows into an engine.

intake manifold–The vehicle component that distributes the fuel-air mixture (and sometimes recirculated exhaust) between the throttle and cylinders.

intermittent–Refers to unexplained vehicle issues that unpredictably arise and disappear.

J

jacking point–A reinforced area underneath a vehicle that acts to properly support a vehicle jack (without causing body damage).

jackshaft–A component of overhead cam engines that assists with distributors, fuel, and oil pumps.

jake brake–A manual exhaust valve shut-off that assists in decelerating large trucks. Closing the exhaust valve creates gas pressure against engine pistons.

jalopy– An obsolete term for any type of worn-out, old automobile.

jamb switch–A light switch (push button) located in a vehicle’s door jamb.

jounce–Refers to a wheel that is experiencing compression.

K

kart–A small, open vehicle with four wheels, powered by a single cylinder gas engine.

keepers–Components of a valve system which lock valve retainers in place.

kickdown–Informal term for downshift of an automatic transmission.

knock–A small, exploding pocket of unspent air-fuel mixture.

knock sensor–A part of an engine control system that monitors and prevents knocks.

L

lateral link–A component of a suspension system that minimizes a wheel’s sideway motion.

leaf spring–A thin (typically steel) spring that is a component of a wheel suspension system.

lift–An upward (vertical) motion.

lightweighting–Refers to car manufacturers using lighter weight, high-strength materials to make greener, fuel-efficient vehicles via reducing their weight.

link–A suspension member fitted with a joint at each end.

live axle–A metal rod that both supports and provides power (motion) to its connecting wheels.

M

M+S–Tire shorthand for mud and snow tire. Any tire with a deep tread designed for traction on snow or mud-covered surfaces.

machining–Creating metal parts by removing excess material via milling or grinding.

MacPherson strut–A suspension device composed of a shock absorber and a coil spring.

magnetic drain plug–A magnetized bolt or plug located in an oil pan that traps metal filings.

main bearings–Bearings located in the engine block that are designed to support a crankshaft.

manual transmission–A mechanism in the drive train with gears to vary the power and torque delivered to the driven wheels. It consists of a lever that the driver operates in conjunction with the clutch to change from one gear to another.

mind-engine–A layout where the vehicle engine is located between the passenger compartment and the rear axle.

mini-van–Similar to sport utility vehicles in that mini-vans are also a type of truck. These vehicles have taken the place of station wagons as the city transport vehicle of choice. They have a higher road clearance so their visibility is greater than cars and they have much more cargo space. However, their higher center of gravity makes them less maneuverable.

muffler–A part of the exhaust system that eliminates noise.

Multi-point injection–Where fuel is delivered directly and separately to each of an engine’s cylinders.

N

NADA–National Automobile Dealers Association.

necking knob–A knob attached to a steering wheel that facilitates one-handed operation.

normally aspirated–An engine that intakes air or "breathes" without the assistance of a supercharger or turbocharger.

neutral steer–A cornering condition in which the traction level of the front and rear tires are the same.

O

OBD–On board diagnostics, a collection of devices that, essentially, keep track of vehicle operation’s fuel emissions.

oil pump–An engine-driven pump that delivers oil, under pressure, to the engine's moving parts.

oil ring–The lowermost piston ring that scrapes off excess oil from the cylinder walls and returns it to the oil pan via vents in the ring and piston.

Original Equipment Manufacturer (OEM) parts–Auto parts made by the company which builds the car or supplies the parts to the original car builder; but it is marketed to auto repair shops (instead of being used in new auto assembly).

overdrive–A small auxiliary gearbox that provides an additional gear ratio. It causes the drive shaft to turn faster than the engine crankshaft, or "overdrive" it. It is engaged manually when under way and reduces fuel consumption.

oversteer–Rear-end fishtailing. Occurs when a car (usually with rear-end drive) is turned too quickly and the rear tires begin to slide due to loss of traction.

P

passive safety features–Those features incorporated into the structural design of the car. Features which the driver cannot control. For example, crumple zones, bumpers, side intrusion beams and roll-over bars.

Positive crankcase ventilation (PCV) valve–devices that return fuel gases back to engine for additional burning, which increases engine efficiency and reduces emissions.

PHEV–Stands for plug-in hybrid electric vehicle.

pick-up–This type of vehicle is a truck. It consists of a closed cab and an open bed. It is popular with the general public because the open bed maximizes the ability to haul cargo.

piston–A cylindrically-shaped metal piece (like a plug) that is moved back and forth in a cylinder by pressure from an explosion, or the introduction of liquid or air. In an engine, an explosion in a cylinder head pushes a piston which in turn moves a crank shaft and turns the car's wheels. In a hydraulic system, like brakes, when the brake pedal is depressed, liquid is pushed against a piston which presses a pad against a rotor, attached to the wheel, slowing the car.

plenum chamber–A component of an intake manifold. This small area assists in evenly distributing air-fuel mixture.

powertrain–All of the items needed to ”power” a car’s wheels, including the engine, transmission, axles, clutch (manual transmission) or torque converter (automatic transmission) and driveshaft.

push–See understeer.

Q

Q–A letter imprinted on a sidewall that is used in tire speed rating. This letter indicates the tire may be safely used for speeds up to, but not exceeding 100 mph.

Q-ship–A high performance vehicle which has a standard performance appearance.

Quad-4–An engine developed by General Motors which, while only having 4 cylinders, is capable of high-performance operation.

quarter panel–The metal sheeting that forms a vehicle’s front or rear corners.

R

rack and pinion steering–Steering system technology that allows for more responsive handling and is found mostly in newer cars. The steering shaft has a small gear at its bottom. It meshes with a toothed bar connected to the steering linkage that controls the two front wheels.

radiator–The device through which air passes to cool a single system in a car. Normally, it is used to cool engine coolant. Conversely it can cool engine oil. In the case of a turbocharged car, a radiator cools the air being forced into the engine and is called an intercooler.

rear axle assembly-The drive shaft, gears and rear axle system that facilitates the changes in power and direction to the rear wheels. Also known as the differential. The term also applies to a front axle assembly (found in rear-engine vehicles).

rear wheel drive–When the engine supplies power only to the rear wheels of a vehicle. This option used to be the standard and still is best used with heavier vehicles.

redline–The maximum number of RPMs at which a given vehicle may be safely operated. This number was, historically, indicated by a red line on a tachometer.

rpm–Means revolutions per minute; it is a measurement of engine speed that refers to the number of times a crankshaft rotates.

S

sedan–A four-door passenger car that is equipped with a separate trunk; usually appears “boxy” because the rear doors are full-sized.

side impact beams–(Also side intrusion impact beams) are steel beams located on the inside of vehicle doors. They are a passive safety feature meant to protect riders from side impact collisions.

smart car-See autonomous vehicle.

spark plug gap-The space between the center and side electrodes of a spark plug across which the spark must jump to ignite the air-fuel mixture in the combustion chamber.

sport utility vehicle–SUV–Basically a jeep with four doors. They ride much higher off the road than sedans which gives drivers higher visibility and the ability to operate on rougher (including unpaved) roads. They usually have plenty of cargo room.

sports car–Is generally a two-seat car which, compared to a sedan, rides lower to the ground, moves faster, has higher horsepower and stiffer suspension. May also be a convertible.

stabilizer bar–A metal bar, usually in a rough U-shape, which links wheels on opposite sides of the car. It tends to keep the wheel motion similar for each side, thus it reduces the roll or sway of a car. As a result, it is frequently also called a roll bar or sway bar. Almost always installed on the front suspension, but many touring or performance cars use rear stabilizer bars also.

station wagon–Also known as wagons. These vehicles have the same “boxy” style as sedans and have four doors; but instead of a trunk, the back of the car is extended to provide a cargo area.

steering response–Refers to the sensitivity of a vehicle to the movement of its steering wheel.

struts–A metal bar or rod that provides the suspension system with structural strength.

suspension–The components on which the vehicle rides, including shock absorbers and struts, that make the ride comfortable. Stiffer suspension gives you a better feel for the road and allows better handling and more predictable cornering. The downside to a stiff suspension is a harsh or bumpy ride.

T

tachometer–A gauge in the dashboard that shows the engine speed in RPMs.

torque–The maximum amount of force produced at a specific speed.

torque converter–The torque converter converts hydraulic pressure within the transmission to mechanical torque which drives the drive shafts and ultimately, the wheels.

traction–Sticking to the ground or getting a grip on the road. If you don't have traction when you are driving, your wheels are just spinning. Your tires won't be transferring the car's power to the road and you won't get the full benefit of the work the engine is doing. If you completely lose traction (like on water) you won't be able to steer the car in the direction you want it to go.

transaxle–Generally found in front wheel drive vehicles. A housing of both the transmission and the differential since there is no need for a driveshaft.

transmission–A mechanism that includes the gears, linking the power produced by the engine to the drive wheels.

turbocharger–An air compressor which provides more air to an engine than it could normally draw. The added air supply increases engine power (see normally aspirated engine).

twin-piston engine–An old form of engine consisting of two pistons located in two, separate cylinders.

twin screw–A vehicle (usually a truck or tractor) equipped with two, engine-driven rear axles.

U

u-channel–U-shaped length of metal used to make reinforced vehicle frames.

u-cylinder engine–See twin piston engine.

undercarriage–See chassis.

understeer–Front-end plowing or diving. Also called nose-diving due to weight shifting to the front of a vehicle during a quick or emergency turn, when the tires plow (push) instead of rotate. This is a tendency in vehicles with front-end drive.

unibody construction–A process for building cars in which sheet metal body parts are pressurized to form the body and chassis as a single piece, as opposed to attaching body parts to a frame.

unitized construction–See unibody construction.

V

valve–A device that can measure or prevent the flow of a liquid or gas. Most internal combustion engines use intake and exhaust valves to control the fuel air mixture into the cylinders and to exhaust burnt gases. Some engines have three, four or even more valves per cylinder to increase total valve area for increased flow, efficiency, and performance.

valvetrain–A vehicle’s complete system of operating valves that facilitate converting engine power to vehicle motion.

VIN (Vehicle Identification Number)–A series of 17 numbers and letters that are stamped on a metal plate which is then attached to a dashboard. The VIN identifies the make, manufacturer, model, year, and place of manufacture for each car.

W

waste gate–A valve that is used to control the boosting power of a turbocharger.

wheelbase–The distance from the center-line of the front wheels to the center-line of the rear wheels. Wheelbase length is a major factor in road stability.

wheelhop–Refers to violent wheel movement in which a wheel (actually tire) actually loses contact with the road surface.

X

X-Axis–Refers to the axis over which a vehicle moves from side to side.

Xylene–A solvent used in grease and paint removal.

Y

Y-Axis–Refers to the axis over which a vehicle moves forwards and backwards.

Y-Block–A model of a V-type engine that features a deep crankcase.

Y-Pipe–A pipe, usually shaped like the letter “y”, such as an exhaust pipe, that branches from one pipe to two.

Z

Z–A letter imprinted on a sidewall that is used in tire speed rating. This letter indicates the tire may be safely used for speeds up to, but not exceeding, 186 mph.

Z'ed–Pronounced zeed, it refers to a vehicle frame that has been cut and raised so that the vehicle can accommodate large tires without raising the vehicle’s original height.

zerk fitting–A ball joint valve that permits the joint to be lubricated without experiencing pressure leaks.

zero-emission vehicle–A vehicle that does not generate exhaust gases (electric vehicles).

zone controls–Controls that maintain a given condition within a specific area, such as distinct areas of a vehicle (such as driver, front passenger, and rear passenger areas).

zero-offset steering–A type of steering system that minimizes steering control during a vehicle’s acceleration or braking.