subsonic

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subsonic

Wikipedia

From sub- +‎ sonic.

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subsonic (not comparable)

(of a sound, scientific) having a frequency too low to be audible
(of a sound, literary) very quiet, almost inaudible
The noise of the ship was all around her. The faint subsonic rumble of the reactor and drive. (Leviathan Wakes, James S. A. Corey)
(of a speed) (aviation) less than the speed of sound (in the same medium, and at the same temperature and pressure)
- 2020 February 9, Alina Selyukh, “British Airways Sets Record, Crossing The Atlantic In Under 5 Hours In Strong Winds”, in NPR:
  But British Airways Flight 112 made the trek in under five hours, setting a new record for the fastest subsonic commercial flight across the Atlantic Ocean.
(fluid mechanics, of a flow) with a Mach number such that 0.3 < Ma < 0.8 (approximately - the exact limits vary between sources)

(of a speed) less than the speed of sound

subsonic (plural subsonics)

		masculine	feminine	masculine	neuter
		singular		plural
nominative- accusative	indefinite	subsonic	subsonică	subsonici	subsonice
nominative- accusative	definite	subsonicul	subsonica	subsonicii	subsonicele
genitive- dative	indefinite	subsonic	subsonice	subsonici	subsonice
genitive- dative	definite	subsonicului	subsonicei	subsonicilor	subsonicelor

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