A car is a complex machine made up of many parts and systems. Understanding the terms and concepts associated with cars can help you make informed decisions when buying, maintaining, and troubleshooting your vehicle. This car terminology glossary contains definitions for common car terms and concepts, from the engine and transmission to the suspension and braking systems. Whether you’re a car enthusiast, a student, or a professional mechanic, this glossary is a useful resource for understanding the inner workings of a car.
ABS (Anti-lock Braking System)
A safety system that prevents the wheels from locking up during braking, allowing the driver to maintain steering control.
Accelerator
A pedal in a vehicle that, when pressed, increases the speed of the engine.
Alternator
A device that generates electricity to power the electrical components of a vehicle.
Amperage
A unit of measurement for electric current.
Anti-roll bar
A bar that connects the left and right wheels on the same axle, used to reduce the amount of body roll (leaning) during turns.
Axle
A shaft that connects the wheels to the vehicle, allowing them to rotate.
Battery
A device that stores electrical energy and supplies it to the starter motor to start the engine.
Belt
A continuous loop of rubber or other material that transfers power from one component to another, such as the alternator to the water pump.
Blower motor
A fan that blows air through the heating and air conditioning system.
Brake
A system that slows or stops a vehicle by pressing pads or shoes against the rotors or drums.
Brake booster
A device that helps the driver apply the brakes with less effort.
Brake caliper
A component that holds the brake pads and presses them against the rotor to create friction and slow or stop the vehicle.
Brake fluid
A fluid that is used to transfer force from the brake pedal to the brakes.
Brake master cylinder
A component that converts the force applied to the brake pedal into hydraulic pressure, which is used to activate the brakes.
Brake pad
A replaceable friction material on the brake caliper that presses against the rotor to slow or stop the vehicle.
Brake rotor
A disk that is attached to the wheel and rotates with it. The brake pads press against the rotor to create friction and slow or stop the vehicle.
Catalytic converter
A device that reduces emissions by converting harmful gases into less harmful ones.
Clutch
A device that allows the engine and transmission to be connected or disconnected, allowing the vehicle to shift gears.
CV joint
A joint that allows the driveshaft to transmit power to the wheels at a constant velocity, even as the suspension moves or the wheels turn.
Differential
A device that allows the wheels to rotate at different speeds, allowing the vehicle to turn.
Distributor
A device that sends electrical current to the spark plugs in the correct sequence, causing the spark that ignites the fuel in the engine.
Drive belt
A belt that transfers power from the engine to components such as the alternator, water pump, and power steering pump.
Drivetrain
The components that transmit power from the engine to the wheels, including the transmission, driveshaft, and differential.
Emission control system
A system that reduces the amount of harmful gases emitted by the vehicle.
Engine
A device that converts fuel into motion, powering the vehicle.
Exhaust system
A system that removes gases from the engine and muffles the noise.
Filter
A device that removes impurities from a fluid, such as the air filter that removes dirt and dust from the air entering the engine.
Fuel pump
A device that pumps fuel from the tank to the engine.
Fuel tank
A container that holds the fuel for the vehicle.
Fuse
A safety device that interrupts the flow of electricity if the current becomes too high, preventing damage to the electrical system.
Gasket
A seal that is used to prevent leaks between two surfaces that are bolted or clamped together.
Grille
A decorative or functional panel located at the front of the vehicle, used to allow air to enter the engine compartment or to protect the radiator from debris.
Head gasket
A gasket that seals the joint between the engine block and the cylinder head.
Headlight
A light mounted at the front of the vehicle that illuminates the road ahead.
Ignition
The system that provides the spark to ignite the fuel in the engine.
Ignition switch
A switch that controls the flow of electricity to the ignition system.
Intake manifold
A component that distributes the air/fuel mixture to the cylinders in the engine.
Lug nut
A nut that secures the wheel to the hub.
Manifold
A component that distributes a substance, such as the intake manifold that distributes the air/fuel mixture to the cylinders or the exhaust manifold that collects the exhaust gases from the cylinders.
Mass air flow (MAF) sensor
A sensor that measures the amount of air entering the engine.
Muffler
A component of the exhaust system that reduces the noise of the exhaust gases.
Oil filter
A filter that removes impurities from the oil, helping to keep the engine lubricated.
Oil pump
A pump that circulates oil through the engine to lubricate the moving parts.
Oil pan
A receptacle at the bottom of the engine that holds the oil.
Oxygen sensor
A sensor that measures the amount of oxygen in the exhaust gases, helping the engine to run efficiently.
Piston
A cylindrical component in the engine that moves up and down in the cylinder, converting the pressure of the expanding gases into motion.
Power steering
A system that uses hydraulic pressure to make it easier to turn the steering wheel.
Pressure plate
A component of the clutch that applies pressure to the clutch disc, allowing it to engage or disengage with the flywheel.
Radiator
A device that dissipates heat from the engine by circulating coolant through it and then through the fins of the radiator, where it is cooled by the air.
Radiator fan
A fan that helps to cool the radiator by blowing air through it.
Radiator hose
A hose that carries coolant between the radiator and the engine.
Rearview mirror
A mirror mounted on the front windshield or dashboard that allows the driver to see what is behind the vehicle.
Resistor
A device that reduces the flow of electricity, such as the resistor in the heater blower motor that reduces the current to a level that the motor can handle.
Rotor
See “Brake rotor.”
Spark plug
A device that produces a spark to ignite the fuel in the engine.
Starter motor
An electric motor that starts the engine by turning the flywheel.
Steering wheel
A wheel that the driver uses to steer the vehicle.
Suspension
The system that connects the wheels to the vehicle and absorbs shock, allowing for a smooth ride.
Throttle
A mechanism that controls the flow of air/fuel mixture into the engine, determining the power output.
Throttle body
A component that houses the throttle and controls the flow of air/fuel mixture into the engine.
Timing belt
A belt that synchronizes the rotation of the camshaft and crankshaft, ensuring that the valves open and close at the proper time.
Transmission
A device that transmits power from the engine to the drive wheels, allowing the vehicle to shift gears and adjust the speed.
Tire
A circular piece of rubber or other material that is mounted on the wheel and makes contact with the ground, providing traction and support for the vehicle.
Tire pressure
The amount of air inside the tire, which affects the tire’s performance and safety.
Tire tread
The pattern of grooves on the surface of the tire that provides traction on the road.
Torque
A measure of the rotational force applied by the engine to the wheels.
Transmission fluid
A fluid that lubricates and cools the transmission, allowing it to operate smoothly.
Turbocharger
A device that increases the air flow to the engine, allowing it to burn more fuel and produce more power.
Valve
A component in the engine that controls the flow of gases in and out of the cylinders.
Voltage
A measure of the electrical potential difference in a circuit.
Water pump
A device that circulates coolant through the engine to keep it cool.
Wheel
A circular component that rotates and supports the vehicle, allowing it to roll.
Wheel bearing
A bearing that allows the wheel to rotate smoothly around the axle.
Wheel hub
The part of the wheel that the lug nuts attach to, securing the wheel to the vehicle.
Jed Lehman
Jed Lehman is a born gearhead who has been working on cars since he could crawl. He inherited his love for auto from his grandfather who owned a maintenance shop in Carlsbad, California. Jed is the driver behind Gearshift, and started this site to provide straightforward, helpful automobile information. From maintenance tips to product reviews, you can find it all here.
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