Understanding Car Terminology: A Glossary of Common Words

Decoding your vehicle owner’s manual or your mechanic’s latest status report can be confusing if you’re not familiar with common car terms. To make matters even more complicated, new technologies are adding words to the lexicon on a regular basis. The next time you come across a term that leaves you feeling confused, consult this handy guide for clarification. These definitions can help with routine maintenance tasks, diagnostics, and repairs as well as describing problems when you bring your car into the shop.

ABS

Short for anti-lock brake system, ABS describes the braking technology that prevents car wheels from locking up when a sudden stop is required.

Air Conditioning

A cooling system that originally appeared in cars in 1970. Abbreviated as AC, it uses refrigerant and a compressor to lower temperatures inside the vehicle to make the ride more comfortable.

Airbags

Safety features consisting of air-filled cushions that deploy immediately in the event of an accident to prevent injury to a vehicle’s occupants.

Air filter

A filter composed of fibrous materials that prevents dirt, dust, debris and other contaminants from entering the engine.

All Wheel Drive

Two-axled vehicle drivetrain capable of providing torque to all of its wheels simultaneously

Brakes (Disc and Drum)

The system that stops your car. Disc brakes use calipers to clasp brake pads to metal discs called brake rotors, which brings the car to a stop. Drum brakes involve a combination of a metal drum and brake shoes, where to shoes press outward to apply pressure to the drum to bring the car to a stop.

Chassis

A blanket description of the base frame of a vehicle and the mechanical parts that are attached to it, including the power train and suspension.

Climate Control

The term used to refer to the heater, air conditioner and defrosting mechanisms in a car. Some vehicles have advanced systems that detect outdoor temperatures and can be adjusted accordingly.

Continuously Variable Transmission

An automatic transmission that can change seamlessly through a continuous range of gear ratios.

Coolant

Also called antifreeze, this combination of ethylene glycol and water protects the climate control system by dispersing excess heat and preventing parts from freezing.

Cylinder

One of the four, six or eight cavities in the engine block in which pistons are located and where combustion action occurs.

Drivability

How smoothly a vehicle accelerates and idles, how well it starts at different temperatures and its ability to adapt to various driving conditions.

Drive Range (EV)

A term that refers to how far an electric vehicle can be driven before you need to recharge the battery.

Drivetrain

All of the parts of a car that work together to deliver power to the car’s wheels. The components differ depending on the type of vehicle (manual, automatic transmission, front-wheel or four wheel-drive). The engine is not included into the drivetrain.

Emissions

An assessment of how many pollutants a car gives off that is measured by EPA standards. Emissions of common gasses must not exceed the maximum levels set by the EPA.

Engine Displacement

Previously measured in cubic inches and now designated in liters, displacement describes the volume of combustion in the engine’s interior.

Fuel Economy

How far a vehicle can travel using a given amount of gasoline. Commonly described in miles per gallon and measured for city and highway driving.

Fuel Injection

A system that delivers a high-pressure fuel stream in an internal combustion engine.

Gearbox

The system of gears controlled by the manual or automatic shifter in a vehicle. The movement of the gears directly influences the movement of the car, and various driving conditions, like cruising on level surfaces,or climbing a hill, use different gear setups.

GPS

A digital navigation system built into many modern vehicles that uses your current location to deliver the best route to a specific destination.

Handling

How well a vehicle moves on straightaways, around corners and over varying degrees of terrain.

Horsepower

A unit of measurement equal to 550 foot pounds per second used to describe the power of a vehicle’s engine. Higher numbers mean more power and the ability to push a car to faster speeds.

Ignition System

The system that generates a spark and controls the timing of the spark that is necessary to ignite the fuel-air mixture and start fuel combustion inside the engine.

Jump Start

An emergency starting procedure used to get a car running when the battery is dead. Jumper cables are attached to the battery of a working vehicle and run to the failed battery to provide a jolt of power.

Keyless Entry

A modern entry system that unlocks doors via a battery-powered remote or key fob instead of requiring you to physically put the key into the lock.

Oil

Lubricant that reduces wear and tear on an engine’s moving parts, prevents overheating and delays the process of corrosion.

Powertrain

This system consists of the combination of the engine and transmission and is often protected by a manufacturer warranty.

PSI

Pounds per square inch, a measurement of pressure most often used to ensure that tires are properly inflated.

Service Book

A record book used to keep track of when service is performed on a vehicle. This is sometimes required in order for your car’s warranty to remain valid and may increase the value of a used car.

Supercharger

A compressor that delivers more air into the engine’s interior. The result is an increase in power but a decrease in fuel efficiency.

Tire Pressure

How much air is in a vehicle’s tires, expressed in pounds per square inch. Some cars have a monitoring system that alerts you to low pressure.

Traction Control

This safety feature minimizes wheel spin and ensures good traction between the tires and the road when a vehicle accelerates. It activates when there is a mismatch between engine torque and throttle input.

Transmission

The internal system that controls the power from the engine and translates it into movement via a manual or automatic shifting mechanism. The term is often used to refer to the gearbox, which we explained above.

Trim Level

The version of a vehicle model that comes equipped with certain features. Higher trim levels come with more/better features at a higher price, while lower-level trim comes with more basic features at a lower overall cost.

Turbocharger

Similar to a supercharger, this device increases vehicle power with the help of an exhaust-driven turbine.

Two Wheel Drive

Vehicles with a drivetrain that allows two wheels to be driven, and receive power and torque from the engine, simultaneously.

VIN

A unique number known as the vehicle identification number that sets a vehicle apart as unique. Digits within the number describe various aspects of the vehicle.