from The American Heritage® Dictionary of the English Language, 4th Edition

  • n. Mach number.
  • Mach, Ernst 1838-1916. Austrian physicist and philosopher who played a central role in the development of logical positivism. His works include the influential Science of Mathematics (1883).

from Wiktionary, Creative Commons Attribution/Share-Alike License

  • proper n. Ernst Mach, Austrian physicist 1838 - 1916.
  • n. a ratio of the speed (of an object, etc.) to the speed of sound in the fluid or other medium through which the object travels. Usually used to describe supersonic speeds.
  • n. the Mach number

from The Century Dictionary and Cyclopedia

  • n. Abbreviations
  • n. of machinery;
  • n. of machinist.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

  • n. Austrian physicist and philosopher who introduced the Mach number and who founded logical positivism (1838-1916)


Sorry, no etymologies found.


  • Most importantly for engineers, Mach Number is the ratio of the speed of sound in the given medium to the speed of the projectile; his work is essential to modern aerodynamics, and through it the word ˜Mach™ has bizarrely entered into popular culture as an icon for razors, sound systems, fighter pilots, and high speed fuels.

    Ernst Mach

  • But not everything always goes according to the plan. flutter testing at the outer edge of the flight envelope, Feuerstein explains that when they were operating very close to the maximum mach operating speed MMO, around .90 Mach, a gentle oscillation could be felt in the cockpit.

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  • Check out this really cool mighty-morphin Mach 5, based on the car from the upcoming Speed Racer movie.

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  • I think the .17 Mach is a fine 100-yard cartridge, and I tested it for accuracy at a conservative 50 yards, where I got. 95-inch five-shot groups.

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  • The launch vehicle (rocket) was expected to reach an altitude of about 100 kilometers (60 miles) on its twenty-two-minute journey that reached a top speed of approximately 5,000 kilometers (3,100 mile) per hour-what is commonly called Mach 5 in aeronautics and astronautics.

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  • Freshly released from fourth grade, I bounced happily in the backseat of our white ’73 Caprice which I called the Mach Five and unconcerned about the lack of luxuries like air conditioning and decent stereo sound.

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  • The jet flew at a speed of about 0.9 Mach which is few notches below the supersonic levels starting at one Mach, which is about 1,236 km per hour.


  • The robot youth, called Mach, had occupied a living human body for the first time, and fallen in love with the human form of Fleta before properly appreciating her nature.

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  • App.Ct. 332 (1993) (unreasonable use of defective and dangerous side climbing system on fire engine); Goulet v. Whitin Mach.

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  • Neil: There are the "efficient" handcycles which are low to the ground and need like the size of a giant truck to haul or store them or there is this evil solid Iron thing I rent called the Mach 3 probably because it weighs three tons!

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  • I already did. By all means recognize Ernst Mach, but his entry must include a reference to his creation of the Mach number, qv.

    None of those Twitter or whatever images convey Mach number, especially those silly cars. Get a picture of a jet fighter breaking the "sound barrier" - there are lots of such pictures, typified by a large circular shock wave of water vapor part way along its fuselage (think of a dog jumping through a hoop that's covered with tissue paper) That illustrates Mach 1, as explained in my separate note.

    Extra descriptive thought. The Concorde flew at Mach 2.2, Boeing's upcoming 787 will cruise at Mach 0.84, and a small Cessna flies at about Mach 0.2. But no one uses Mach numbers for anything slower than about Mach 0.75.

    I'm a former military and airline pilot, now an aviation journalist. Email me for additional info, or explanations of unusual aeronautical terms and their meaning and usage.


    June 15, 2009

  • The physicist Ernst Mach was certainly quite well known in his time. But I think your bubble size is grossly in error for the 1950 - 2010 timeframe. Mach postulated the Mach number, which describes an aircraft's speed relative to the ambient speed of sound. Mach 0.5 denotes half the speed of sound: Mach 1.0 equals the speed of sound, and Mach 2 is twice the speed of sound, etc. See the Concise Oxford. You don't have Mach Number in your definitions yet. When you check its usage over the period I describe, you'll have to change the scale of your bubble graph enormously!


    June 15, 2009