or Mach

  1. a number indicating the ratio of the speed of an object to the speed of sound in the medium through which the object is moving. Abbreviation: M

Origin of mach

after E. Mach
Also called mach number, Mach number.


[mahk; German mahkh]
  1. Ernst [ernst] /ɛrnst/, 1838–1916, Austrian physicist, psychologist, and philosopher.

mach. Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018

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British Dictionary definitions for mach


  1. short for Mach number


  1. Ernst (ɛrnst). 1838–1916, Austrian physicist and philosopher. He devised the system of speed measurement using the Mach number. He also founded logical positivism, asserting that the validity of a scientific law is proved only after empirical testing
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Word Origin and History for mach


measure of speed relative to the speed of sound (technically Mach number), 1937, named in honor of Austrian physicist Ernst Mach (1838-1916).

Online Etymology Dictionary, © 2010 Douglas Harper

mach in Science


[mäk, mäKH]Ernst 1838-1916
  1. Austrian physicist and philosopher who experimented with supersonic projectiles and the flow of gases, obtaining early photographs of shock waves and gas jets. His work laid an important foundation for later developments in the science of projectiles and aeronautical design, and the Mach number and Mach bands were named for him.
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.