Definition of Mach in English:

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Pronunciation: /mɑːk/
(also Mach number)


The ratio of the speed of a body to the speed of sound in the surrounding medium. It is often used with a numeral (as Mach 1, Mach 2, etc.) to indicate the speed of sound, twice the speed of sound, etc.
Example sentences
  • A Mach number is a measure of airspeed, and not of ground speed.
  • When the P - 38 wing developed a supersonic enclosure at the critical Mach number, the center of pressure moved aft, causing the nose to tuck down.
  • The party atmosphere as we roared across the Atlantic at twice the speed of sound, Mach 2, 1,350 miles per hour, at the very edge of space.


1930s: named after Ernst Mach (see Mach, Ernst).

For editors and proofreaders

Line breaks: Mach

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