radar

[rey-dahr]
noun
1.
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.
2.
a means or sense of awareness or perception: lobbyists working under the media's radar.

Origin:
1940–45, Americanism; ra(dio) d(etecting) a(nd) r(anging)

antiradar, noun, adjective
Dictionary.com Unabridged
Based on the Random House Dictionary, © Random House, Inc. 2014.
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Collins
World English Dictionary
radar (ˈreɪdɑː)
 
n
1.  Former name: radiolocation 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
2.  the equipment used in such detection
 
[C20 ra(dio) d(etecting) a(nd) r(anging)]

Collins English Dictionary - Complete & Unabridged 10th Edition
2009 © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins
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Etymonline
Word Origin & History

radar
1941, acronym (more or less) for radio detecting and ranging. The U.S. choice, it won out over British radiolocation.
Online Etymology Dictionary, © 2010 Douglas Harper
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American Heritage
Science Dictionary
radar  [%PREMIUM_LINK%]     (rā'där)  Pronunciation Key 


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  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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American Heritage
Cultural Dictionary

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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American Heritage
Abbreviations & Acronyms
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.
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Example sentences
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.
Images for radar
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