A disc brake assembly. Wheel rotation is slowed by friction when the hydraulic pistons squeeze the …—© Merriam-Webster Inc.

Device for decreasing the speed of a body or stopping its motion. Most brakes act on rotating mechanical elements and absorb kinetic energy mechanically, hydrodynamically, or electrically. Mechanical brakes are the most common; they dissipate the kinetic energy as heat generated by mechanical friction between a rotating drum or disk and a stationary friction element. A hydrodynamic (fluid) brake has a rotor (rotating element) and a stator (stationary element). Resistance to rotation is created by fluid friction and circulation of the liquid (usually water) from a series of pockets in the rotor to a series of complementary pockets in the stator. See also air brake.

This entry comes from Encyclopædia Britannica Concise.
For the full entry on brake, visit

Seen & Heard

What made you look up brake? Please tell us what you were reading, watching or discussing that led you here.

Get Our Free Apps
Voice Search, Favorites,
Word of the Day, and More
Join Us on FB & Twitter
Get the Word of the Day and More