air brake

noun

1. : a brake operated by a piston driven by compressed air from reservoirs connected to brake cylinders by triple valves which upon reduction of air pressure in the brake pipe automatically admit air from the reservoirs into the brake cylinder

2. : a surface (as an aileron) that may be projected into the airstream for increasing the resistance and lowering the speed of an airplane

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1. a brake or system of brakes operated by compressed air.

2. Aeron. a device for reducing the air speed of an aircraft by increasing its drag.

3. a device for stopping the sails of a windmill by disrupting the flow of air around them.

[1870-75, Amer.]

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air brake UK US noun [countable] [singular air brake plural air brakes]

a type of brake (=piece of equipment to make a vehicle stop or go more slowly) that works using compressed air, for example on a bus or truck

Thesaurus: equipment and systems in cars and other road vehicles_hyponym

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air brake,

1. a brake or system of brakes operated by forcing compressed air against a piston or pistons.

2. = speed brake. (Cf. ↑speed brake)

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n. a brake worked by air pressure

■ a movable flap or other device on an aircraft to reduce its speed

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ˈair brake f22 [air brake air brakes] noun

a ↑brake in a vehicle that is worked by air pressure