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[rey-dahr] /ˈreɪ dɑr/
Electronics. a device for determining the presence and location of an object by measuring the time for the echo of a radio wave to return from it and the direction from which it returns.
a means or sense of awareness or perception:
lobbyists working under the media's radar.
Origin of radar
1940-45, Americanism; ra(dio) d(etecting) a(nd) r(anging)
Related forms
antiradar, noun, adjective Unabridged
Based on the Random House Dictionary, © Random House, Inc. 2015.
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Examples from the web for radar
  • radar works by recording radio waves that have been reflected from the object under observation.
  • Community colleges can no longer fly under the radar.
  • Another way to get rewards under the radar screen is via perks.
  • radar gun emits a continuous stream of microwaves at a preset frequency.
  • radar typically is used to keep track of larger objects, such as airplanes.
  • The controllers' radar only shows planes' approximate positions, so they must space them well apart.
  • The radar-responsive tag stays asleep until it is awakened by a radar pulse.
  • It must have a built-in radar or sonar beam to get it to a safe landing.
  • Scientists strap radar rigs onto honeybees to test a theory about the buzzing insects' bizarre method of communication.
  • Then a new radar detector would come out to help drivers evade it.
British Dictionary definitions for radar


a method for detecting the position and velocity of a distant object, such as an aircraft A narrow beam of extremely high-frequency radio pulses is transmitted and reflected by the object back to the transmitter, the signal being displayed on a radarscope. The direction of the reflected beam and the time between transmission and reception of a pulse determine the position of the object Former name radiolocation
the equipment used in such detection
Word Origin
C20 ra(dio) d(etecting) a(nd) 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 radar

"electronic system for locating objects by means of radio waves," 1941, acronym (more or less) from radio detecting and ranging. The U.S. choice, it won out over British radiolocation. Figurative from 1950.

Online Etymology Dictionary, © 2010 Douglas Harper
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radar in Science

  1. A method of detecting distant objects and determining their position, speed, material composition, or other characteristics by causing radio waves to be reflected from them and analyzing the reflected waves. The waves can be converted into images, as for use on weather maps.

  2. The equipment used in such detecting. See also Doppler effect, lidar, sonar.

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

radar definition

A method of finding the position and velocity of an object by bouncing a radio wave off it and analyzing the reflected wave. Radar is an acronym for radio detection and ranging.

Note: Police use radar techniques to determine the speed of automobiles.
The American Heritage® New Dictionary of Cultural Literacy, Third Edition
Copyright © 2005 by Houghton Mifflin Company.
Published by Houghton Mifflin Company. All rights reserved.
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Related Abbreviations for radar


radio detecting and ranging
The American Heritage® Abbreviations Dictionary, Third Edition
Copyright © 2005 by Houghton Mifflin Company.
Published by Houghton Mifflin Company. All rights reserved.
Cite This Source

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