Any device designed to slow or to stop the motion of a vehicle or machine by the use of friction in a controlled manner: A brake is a mechanical device that stops a car by converting its kinetic energy into heat.

Most cars use disk brakes, which use pads to cause friction against disks inside the wheels to slow them down or to stop them.

An electronic control system that applies a car's brakes in short bursts to prevent skidding: The antilock brake system in a cr allows the driver to keep control of the car and to shorten the braking distance, especially on slippery surfaces.

Jan knows a guy who's addicted to brake fluid. He says he can stop any time.

An engine's horsepower measured without the loss in power caused by the gearbox, generator, differential, water pump, and other auxiliaries: Brake horsepower (abbreviated as bhp or b.hp) is determined by a brake attached to the drive shaft and recorded on a dynamometer (device used in testing for efficiency and torque).