sound barrier (countable and uncountable, plural sound barriers)
- (uncountable) Sonic barrier, the sudden increase in drag (resistance) and other effects experienced by moving objects when their speed approaches that of sound or becomes supersonic (which used to be considered a barrier to higher speeds).
- (countable) A noise barrier, a structure beside a highway designed to reduce the noise of traffic.
- 2021 October 6, Howard Johnston, “Regional News: Anglia”, in RAIL, number 941, page 29:
- St Ives: The guided busway on the old railway alignment to Cambridge has just passed its tenth anniversary. Railfuture has noted its down-at-heel physical appearance, with dirty concrete beams, damaged sound barriers, and unmanaged vegetation.
drag and other effects of approaching the speed of sound