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mach

or Mach

[mahk]
See more synonyms on Thesaurus.com
noun
  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.

mach number

or Mach number

noun
  1. mach.

Origin of mach number

First recorded in 1935–40
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018
British Dictionary definitions for mach number

Mach1

noun
  1. short for Mach number

Mach2

noun
  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

Mach number

noun
  1. (often not capital) the ratio of the speed of a body in a particular medium to the speed of sound in that medium. Mach number 1 corresponds to the speed of soundOften shortened to: Mach

Word Origin

C19: named after Ernst Mach
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 number

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 number in Science

Mach

[mäk, mäKH]
  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.

Mach number

  1. The ratio of the speed of a body to the speed of sound in a particular medium, usually the Earth's atmosphere. For example, an aircraft flying through air at twice the speed of sound has a Mach number of 2. The Mach number of an aircraft travelling at a given velocity depends on the altitude of the aircraft and other atmospheric conditions that affect the speed of sound near the aircraft. See also subsonic supersonic transonic.
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
mach number in Culture

Mach number

[(mahk)]

The speed of an object, measured in multiples of the speed of sound. Thus, an airplane traveling at the speed of sound is said to be at Mach 1; at twice the speed of sound, it is said to be at Mach 2.

Note

The unit is named after Ernst Mach, an Austrian physicist of the nineteenth century.
The New Dictionary of Cultural Literacy, Third Edition Copyright © 2005 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.