/ Dictionary / Index A air brake: Meaning and Definition of Find definitions for: air' brake" Pronunciation: [key] a brake or system of brakes operated by compressed air. a device for reducing the air speed of an aircraft by increasing its drag. a device for stopping the sails of a windmill by disrupting the flow of air around them. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: airbrake (Thesaurus) air-bound airbrasive Related Content Daily Word Quiz: acquiesce Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language