AskDefine | Define brake

Dictionary Definition



1 a restraint used to slow or stop a vehicle
2 any of various ferns of the genus Pteris having pinnately compound leaves and including several popular houseplants
3 large coarse fern often several feet high; essentially weed ferns; cosmopolitan [syn: bracken, pasture brake, Pteridium aquilinum]
4 an area thickly overgrown usually with one kind of plant


1 stop travelling by applying a brake; "We had to brake suddenly when a chicken crossed the road"
2 cause to stop by applying the brakes; "brake the car before you go into a curve"

User Contributed Dictionary



From braeke.


  • , /bɹeɪk/, /breIk/
  • Rhymes with: -eɪk



  1. A device used to slow or stop a vehicle, by friction; often installed on the wheels.
  2. something that slows or stops an action
  3. the handle, manned by up to six men, by which a ship's pump was worked
  4. a thicket, or an area overgrown with briers etc.
  5. A type of machine for bending sheet metal. (See wikipedia.)



  1. To operate a brake.
  2. To be stopped or slowed, as if by a brake.
  3. past tense of break
    • Exodus 32:3, KJV: And all the people brake off the golden earrings...


Extensive Definition

A brake is a device for slowing or stopping the motion of a machine or vehicle, or alternatively a device to restrain it from starting to move again. The kinetic energy lost by the moving part is usually translated to heat by friction. Alternatively, in regenerative braking, much of the energy is recovered and stored in a flywheel, capacitor or turned into alternating current by an alternator, then rectified and stored in a battery for later use.
Note that kinetic energy increases with the square of the velocity (E = 1/2·m·v2 relationship). This means that if the speed of a vehicle doubles, it has four times as much energy. The brakes must therefore dissipate four times as much energy to stop it and consequently the braking distance is four times as long.
Brakes of some description are fitted to most wheeled vehicles, including automobiles of all kinds, trucks, trains, motorcycles, and bicycles. Baggage carts and shopping carts may have them for use on a moving ramp.
Some aeroplanes are fitted with wheel brakes on the undercarriage. Some aircraft also feature air brakes designed to slow them down in flight. Notable examples include gliders and some WWII-era fighter aircraft. These allow the aircraft to maintain a safe speed in a steep descent. The Saab B 17 dive bomber used the deployed undercarriage as an air brake.
Deceleration and avoiding acceleration when going downhill can also be achieved by using a low gear; see engine braking.
Friction brakes on cars store the heat in the rotating part (drum brake or disc brake) during the brake application and release it to the air gradually.

Effects on noise pollution

The action of braking for motor vehicles produces recognizable sound level emissions, varying with the specific tire types and with the roadway surface type produces considerable effect upon sound levels or noise pollution emanating from moving vehicles. There is a considerable range in acoustical intensities produced depending upon the specific tire tread design and the rapidity of deceleration required to slow the vehicle.
brake in Bulgarian: Спирачка
brake in Czech: Brzda
brake in German: Bremse
brake in Estonian: Pidur
brake in Spanish: Freno
brake in Esperanto: Bremsilo
brake in Persian: ترمز
brake in French: Frein
brake in Scottish Gaelic: Breig (càr)
brake in Croatian: Kočnice
brake in Indonesian: Rem
brake in Italian: Freno
brake in Hebrew: בלם (מכשיר)
brake in Hungarian: Fék
brake in Dutch: Rem
brake in Japanese: ブレーキ
brake in Polish: Hamulec
brake in Portuguese: Travão
brake in Russian: Тормоз
brake in Simple English: Brake
brake in Finnish: Jarru
brake in Swedish: Broms
brake in Tajik: Тормоз
brake in Turkish: Fren

Synonyms, Antonyms and Related Words

arrest, backpedal, backwater, bar, bearing rein, bit, block, boscage, bosket, bring to, bring up short, canebrake, ceja, chain, chamisal, chaparral, check, checkmate, checkrein, chock, clip the wings, clog, constraint, control, coppice, copse, copsewood, countercheck, covert, curb, curb bit, cut short, dam, damper, deadlock, decelerate, delay, detain, doorstop, drag, drag sail, draw rein, drift anchor, drift sail, drogue, ease off, ease up, fetter, freeze, frith, halt, hold back, hold in check, hold up, holdback, impede, keep back, let down, let up, lose ground, lose momentum, lose speed, martingale, moderate, motte, obstruct, pelham, pull up, put paid to, reef, rein, rein in, relax, remora, restraint, restriction, retard, scotch, sea anchor, set back, shackle, slack off, slack up, slacken, slow, slow down, slow up, snaffle, spoke, stalemate, stall, stay, stem, stem the tide, stop, stop cold, stop dead, stop short, stymie, take in sail, thicket, thickset, throttle down, trammel
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