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[suhb-son-ik] /sʌbˈsɒn ɪk/
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
Related forms
subsonically, adverb Unabridged
Based on the Random House Dictionary, © Random House, Inc. 2015.
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Examples from the web for subsonic
  • Flight engineers define three categories of speed: subsonic, supersonic, and hypersonic.
  • So the region where the flow changes from subsonic to supersonic is an event horizon.
  • Also, supersonic speeds produce shock that is not a part of subsonic velocities.
British Dictionary definitions for subsonic


being, having, or travelling at a velocity below that of sound: a 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
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subsonic in Science
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.

The American Heritage® Science Dictionary
Copyright © 2002. Published by Houghton Mifflin. All rights reserved.
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