the sound barrier
noun/ðə ˈsaʊnd bæriə(r)/
/ðə ˈsaʊnd bæriər/
[singular]- the point at which an aircraft’s speed is the same as the speed of sound, causing reduced control, a very loud noise (called a sonic boom) and various other effects
- to break the sound barrier (= to travel faster than the speed of sound)
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the sound barrier