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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. 2015.
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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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Related Abbreviations for sonar


sound navigation and ranging
The American Heritage® Abbreviations Dictionary, Third Edition
Copyright © 2005 by Houghton Mifflin Company.
Published by Houghton Mifflin Company. All rights reserved.
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