noting or pertaining to a speed less than that of sound in air at the same height above sea level.
Origin of subsonic
1940–45; sub- + -sonic
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019
Examples from the Web for subsonic
Historical Examples of subsonic
being, having, or travelling at a velocity below that of sounda subsonic aircraft
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
Having a speed less than that of sound in a designated medium, usually air; having a velocity less than Mach 1. Compare hypersonic supersonic transonic.
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