REFERENCE

Automotive glossary

Short explanations of the terms used on specification pages. Definitions describe general concepts; check each vehicle page for what is actually listed.

Acceleration 0-100 km/h
The time a vehicle needs to reach 100 km/h from a standstill, a common shorthand for overall performance.
Anti-lock braking system (ABS)
A safety system that rapidly releases and reapplies brake pressure so the wheels keep rotating during hard braking, letting the driver keep steering control.
Battery capacity
The amount of energy a traction battery can store, stated in kilowatt-hours. Larger capacity generally allows a longer electric driving range.
Bore and stroke
The diameter of a cylinder (bore) and the distance the piston travels inside it (stroke). Together they determine the displacement of the engine.
CO2 emissions
The amount of carbon dioxide released per kilometre under a standardised test. Lower figures usually go hand in hand with lower fuel consumption.
Compression ratio
The ratio between the largest and smallest volume of a cylinder as the piston moves. Higher ratios improve efficiency but may require higher-octane fuel.
Continuously variable transmission (CVT)
An automatic gearbox that changes ratios smoothly rather than in fixed steps, keeping the engine at an efficient speed. It is one of several transmission types, alongside manual, torque-converter automatic and dual-clutch gearboxes.
Curb weight
The weight of the vehicle with all standard equipment and fluids but without passengers or cargo.
Displacement
The total volume swept by all pistons inside the cylinders, usually stated in cubic centimetres or litres. Larger displacement often means more power but higher consumption.
Drive type
Which wheels receive power: front-wheel drive, rear-wheel drive or all-wheel drive. All-wheel drive can send power to every wheel for extra traction.
Driving range
The distance an electric or plug-in vehicle can travel on a full charge under a stated test cycle. Temperature, speed and load change the real result.
Electronic stability control (ESC)
A system that brakes individual wheels and adjusts engine power when it detects the car sliding or skidding, helping it follow the intended path.
Engine speed (rpm)
Revolutions per minute of the engine crankshaft. Power and torque figures are usually quoted together with the engine speed at which they are reached.
Forced induction
A turbocharger or supercharger compresses the air entering the engine so a smaller engine can produce more power. Naturally aspirated engines draw air without a compressor.
Fuel consumption
How much fuel a vehicle uses over a set distance, commonly litres per 100 km. City, highway and combined figures come from standardised test cycles and real-world results vary.
Gross vehicle weight
The maximum permitted weight of the vehicle including passengers, cargo and fluids, as set by the manufacturer.
Ground clearance
The gap between the lowest point of the underbody and the road. More clearance helps on rough roads and steep driveway ramps.
Horsepower
A unit of engine or motor output. One metric horsepower is about 0.735 kilowatts. Peak power is normally reached at high engine speed.
Kilowatt
The metric unit of power used for engines and electric motors. One kilowatt is roughly 1.36 metric horsepower.
Mild hybrid
A car with a small electric motor and battery that assist the combustion engine and recover braking energy but cannot drive on electricity alone.
Number of gears
How many fixed forward ratios a gearbox offers. More gears can improve economy and refinement; continuously variable transmissions have no fixed steps.
Top speed
The highest speed a vehicle can sustain under manufacturer test conditions. Some cars are electronically limited below their mechanical potential.
Torque
The twisting force the engine or motor delivers to the wheels, usually stated in newton-metres. Strong torque at low engine speed makes a car feel responsive when pulling away or towing.
Track width
The distance between the centres of the two wheels on the same axle. A wider track generally improves stability in corners.
Traction control
A system that reduces engine power or brakes a spinning wheel when it loses grip during acceleration, helping the car pull away on slippery surfaces.
Turning radius
The radius of the tightest circle a vehicle can drive with the steering at full lock. A smaller figure means the car needs less room to turn around.
Valves per cylinder
The number of intake and exhaust valves in each cylinder. Four valves per cylinder is common and helps the engine breathe at higher speeds.
Wading depth
The deepest standing water a vehicle is designed to drive through slowly without damage to the engine or electronics.
Wheelbase
The distance between the centres of the front and rear wheels. A longer wheelbase usually gives more cabin space and a calmer ride; a shorter one helps agility and parking.