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[soh-nahr] /ˈsoʊ nɑr/
a method for detecting and locating objects submerged in water by echolocation.
the apparatus used in sonar.
Also called, British, asdic.
Origin of sonar
1940-45; so(und) na(vigation) r(anging) Unabridged
Based on the Random House Dictionary, © Random House, Inc. 2018.
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Examples from the Web for sonar
Contemporary Examples
Historical Examples
  • The sonar equipment showed what kind of rock it was—iron and basalt.

    The Minus Woman Russell Robert Winterbotham
  • But what good would it do anyone to stick a sonar device on an island like this?

    The Wailing Octopus Harold Leland Goodwin
  • For instance, there must have been a sonar unit near where we swam at St. Thomas.

    The Wailing Octopus Harold Leland Goodwin
  • The boys were familiar with sonar because of the Spindrift work on the Submobile.

    The Wailing Octopus Harold Leland Goodwin
  • He adjusted the sonar pickups, turned the amplifier to maximum, and listened intently.

    Way of a Rebel Walter M. Miller
  • It was given to drink jardar magn svalkaldr sr and sonar dreyri.

    Teutonic Mythology, Vol. 1 of 3 Viktor Rydberg, Ph.D.
  • He listened for code on the sonar equipment, but heard only the weird and nameless sea-sounds.

    Way of a Rebel Walter M. Miller
  • Thus the sonar waves would appear to be striking no obstacle—and no echo would return to the sonarscopes on the search craft!

British Dictionary definitions for sonar


a communication and position-finding device used in underwater navigation and target detection using echolocation
Word Origin
C20: from so(und) na(vigation and) r(anging)
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
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Word Origin and History for sonar

apparatus for detection underwater, 1946, from first letters of "sound navigation ranging," on pattern of radar.

Online Etymology Dictionary, © 2010 Douglas Harper
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sonar in Science

  1. Short for sound navigation and ranging. A method of detecting, locating, and determining the speed of objects through the use of reflected sound waves. A sound signal is produced, and the time it takes for the signal to reach an object and for its echo to return is used to calculate the object's distance. The Doppler effect can also be used to determine the object's relative velocity. Electronic sonar systems are used for submarine navigation and for detecting schools of fish. Some mammals, especially bats, use biological sonar to navigate and detect prey in dark conditions, commonly called echolocation.

  2. The equipment or physiology used in doing this. See also Doppler effect, lidar, radar.

The American Heritage® Science Dictionary
Copyright © 2002. Published by Houghton Mifflin. All rights reserved.
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