radar
Americannoun
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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.
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a means or sense of awareness or perception.
lobbyists working under the media's radar.
noun
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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
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the equipment used in such detection
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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.
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The equipment used in such detecting.
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See also Doppler effect lidar sonar
Discover More
Police use radar techniques to determine the speed of automobiles.
Other Word Forms
Etymology
Origin of radar
1940–45, ra(dio) d(etecting) a(nd) r(anging)
Compare meaning
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Explanation
Radar is a system for locating objects by bouncing radio waves off of them. Air traffic controllers use radar to keep track of exactly where airplanes are. Radar is a scientific method of figuring out where objects are — it's used today by the Coast Guard, astronomers, and the military, among others. Researchers in the late 1800's and early 1900's realized that radio waves could be reflected off solid objects, and by World War II radar was frequently used to detect ships and planes. The name radar is a shortened form of the phrase "radio detecting and ranging."
Vocabulary lists containing radar
Back-Words: Palindromes
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World War II
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Example Sentences
Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.
While the war in the Middle East was top of the RBA’s concerns, a surge in investment related to the build-out of artificial-intelligence infrastructure was also on the bank’s radar.
From The Wall Street Journal ● Aug. 25, 2026
Sentinel-1 is especially valuable for monitoring remote glaciers because its radar instruments can collect observations both day and night and can see through cloud cover.
From Science Daily ● Aug. 25, 2026
The entire project -- which includes replacing ageing radar -- is supposed to be completed by 2028.
From Barron's ● Aug. 23, 2026
She said she had visited the site this week and spoke to staff who "can't just turn the radar off and leave".
From BBC ● Aug. 20, 2026
Under the radar, and without a formal charter, he had transformed Truman into something like a high school for the performing arts.
From "Drama High" by Michael Sokolove
Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.
