brake light

noun

a taillight that lights up as the driver of a vehicle steps on the brake pedal to slow down or stop.

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British Dictionary definitions for brake light

brake light

noun

a red light attached to the rear of a motor vehicle that lights up when the brakes are applied, serving as a warning to following driversAlso called: stoplight

Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012