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Synonyms

mach

1 American  
[mahk] / mɑk /
Or Mach

noun

  1. mach number.


Mach 2 American  
[mahk, mahkh] / mɑk, mɑx /

noun

  1. Ernst 1838–1916, Austrian physicist, psychologist, and philosopher.


mach. 3 American  

abbreviation

  1. machine.

  2. machinery.

  3. machinist.


Mach 1 British  
/ mæk /

noun

  1. short for Mach number

"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

Mach 2 British  
/ max /

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

"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

Mach Scientific  
/ 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.


Usage

How fast is Mach 1? A Mach number is the ratio of an object's speed in a given medium to the speed of sound in that medium. Mach 1, then, is the speed of sound, around 761 mph at sea level on a standard day. The term is also used as a metaphor for high speeds more generally. How to pronounce Mach 1[ mahk wuhn ]

Etymology

Origin of mach

After Ernst Mach

Example Sentences

Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.

See Examples For:

After the results, Bhattacharya said, the BJP would send "different kinds of small fish" to Banerjee's house and invite her party workers over for mach bhaat, Bengali for fish and rice.

From BBC Apr. 20, 2026

Air Force Captain Kristin "BEO" Wolfe performs the "high-speed pass" maneuver at approximately .95 mach, which is just below the speed of sound, at the 2020 Fort Lauderdale Air Show in Fort Lauderdale, Florida, U.S.

From Reuters Nov. 16, 2021

I will be curious to see what mach his framework has achieved by then.

From Forbes Mar. 10, 2013

A "mach meter," an aerial speedometer, in view of passengers in the first few rows reached mach 1.

From Time Magazine Archive

After making prodigious havock in many other places, Alfonzo returned to Columbo with mach spoil and many prisoners.

From A General History and Collection of Voyages and Travels — Volume 06 Arranged in Systematic Order: Forming a Complete History of the Origin and Progress of Navigation, Discovery, and Commerce, by Sea and Land, from the Earliest Ages to the Present Time by Robert Kerr

The first dates to the 1880s and was introduced by physicist Ernst Mach.

From Science Daily Jul. 17, 2026

Larry Ryan drives a 2021 Mustang Mach E but his “wife refuses to ride in the car on any trips over 150 miles for fear of running out of charge.”

From The Wall Street Journal Jul. 11, 2026

El Segundo-based industrial supplies company Advanced Manufacturing Company of America and Huntington Beach-based aerospace company Mach Industries each raised $300 million.

From Los Angeles Times Jul. 10, 2026

Hypersonic means Mach 5—five times the speed of sound.

From The Wall Street Journal Jun. 14, 2026

With Mach 1 achieved, engineering imaginations broke free of all previous speed limits.

From "Hidden Figures" by Margot Lee Shetterly

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