subsonic

adjective

sub·​son·​ic ˌsəb-ˈsä-nik How to pronounce subsonic (audio)
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
3
: infrasonic sense 1
subsonically
ˌsəb-ˈsä-ni-k(ə-)lē How to pronounce subsonic (audio)
adverb

Examples of subsonic in a Sentence

Recent Examples on the Web
Examples are automatically compiled from online sources to show current usage. Read More Opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback.
In particular, the shape of the weapon looks much like a conventional subsonic cruise missile. — Geoff Brumfiel, NPR, 18 June 2026 At subsonic speeds, the airflow over an airframe consists of relatively smooth, though complex, streams. — David Szondy june 04, New Atlas, 4 June 2026 Many are subsonic, though some newer systems can be supersonic or hypersonic. — Atharva Gosavi, Interesting Engineering, 30 June 2026 The Tomahawk is an advanced subsonic cruise missile that is primarily launched from submarines and ships and used to conduct precision strikes. — Zachary Folk, Forbes.com, 10 Mar. 2026 See All Example Sentences for subsonic

Word History

Etymology

International Scientific Vocabulary

First Known Use

1920, in the meaning defined at sense 3

Time Traveler
The first known use of subsonic was in 1920

Rhymes for subsonic

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Browse Nearby Words

subsolar point
subsonic
subsonic flow
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Cite this Entry

“Subsonic.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/subsonic. Accessed 7 Jul. 2026.

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Kids Definition

subsonic

adjective
sub·​son·​ic ˌsəb-ˈsän-ik How to pronounce subsonic (audio)
ˈsəb-
1
: of, relating to, or being a speed less than that of sound in air
2
: moving, capable of moving, or using air currents moving at a subsonic speed
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