noun
a brake on an automobile that magnifies a small force applied to the brake pedal into a proportionately larger force applied to slow or stop the vehicle
• Hypernyms: ↑brake
• Hyponyms: ↑airbrake
• Part Holonyms: ↑motor vehicle, ↑automotive vehicle
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noun : automotive brake with engine power used to amplify the torque applied at the pedal by the driver
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an automotive brake set by pressure from some power source, as a compressed-air reservoir, in proportion to a smaller amount of pressure on the brake pedal.
[1895-1900]
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power brake,
a brake in a motor vehicle that uses the vacuum produced by the engine to force hydraulic fluid or compressed air to the brake shoes of the wheel, requiring very little pressure on the brake pedal to stop the vehicle.
Useful english dictionary. 2012.