sub·​son·​ic | \ ˌsəb-ˈsä-nik How to pronounce subsonic (audio) \

Definition of subsonic

1 : of, relating to, or being a speed less than that of sound in air
2 : moving, capable of moving, or utilizing air currents moving at a subsonic speed

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Other Words from subsonic

subsonically \ ˌsəb-​ˈsä-​ni-​k(ə-​)lē How to pronounce subsonic (audio) \ adverb

Examples of subsonic in a Sentence

Recent Examples on the Web The subsonic Hawks are the only fighters permanently based in the east, where the Chinese planes flew their provocative mission. David Axe, Forbes, 27 Sep. 2021 The Concorde’s fares were about 30% more than subsonic first class fares. Jennifer Alsever, Fortune, 18 Sep. 2021 Tuo Chiang carries eight subsonic Hsiung Feng II anti-ship missiles and eight supersonic Hsiung Feng III anti-ship missiles in two pairs of quad launchers. David Axe, Forbes, 10 Sep. 2021 The fuel had to be stable under temperatures as low as -90° F. in subsonic cruising flight during aerial refueling, and to over 350° F. at high cruising speeds when it would be fed into the engine fuel system. Clarence L. Johnson, Popular Mechanics, 12 Aug. 2021 Certain strands of the environmental movement have long opposed supersonic flight, alleging that supersonic aircraft will burn more fuel per passenger than subsonic planes and thus produce more pollution. Andrew Follett, National Review, 12 June 2021 The irony surrounding the 50th anniversary of the breaking of the sound barrier is that the two most modern planes in the Air Force’s arsenal, the F-117 fighter and the B-2 bomber, are subsonic, having traded speed for stealth. Rob Verger, Popular Science, 8 Dec. 2020 During subsonic flight, air molecules move to one side or another of an oncoming wing. Anna Russel, The New Yorker, 3 Aug. 2021 From the very start, engineers planned to use jet engines to drive propellers, providing a more efficient powerplant combination at subsonic speeds. Walter J. Boyne And Alex Hollings, Popular Mechanics, 23 May 2021

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'subsonic.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

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First Known Use of subsonic

1920, in the meaning defined at sense 3

History and Etymology for subsonic

International Scientific Vocabulary

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Time Traveler for subsonic

Time Traveler

The first known use of subsonic was in 1920

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Dictionary Entries Near subsonic

subsolar point


subsonic flow

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Last Updated

5 Oct 2021

Cite this Entry

“Subsonic.” Dictionary, Merriam-Webster, Accessed 25 Oct. 2021.

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More Definitions for subsonic



English Language Learners Definition of subsonic

: slower than the speed of sound


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