a method for detecting and locating objects submerged in water by echolocation.
the apparatus used in sonar.

Origin of sonar

1940–45; so(und) na(vigation) r(anging)
Also called, British, asdic. Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

Examples from the Web for sonar

Contemporary Examples of sonar

Historical Examples of sonar

  • 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

British Dictionary definitions for sonar



a communication and position-finding device used in underwater navigation and target detection using echolocation

Word Origin for sonar

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

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

Science definitions for sonar



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.
The equipment or physiology used in doing this. See also Doppler effect lidar radar.
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.