radar

American  

[rey-dahr] / ˈreɪ dɑr /

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.

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radar British  

/ ˈreɪdɑː /

noun

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

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radar Scientific  

/ rā′där /

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.

3. See also Doppler effect lidar sonar

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radar Cultural  

1. 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 ra dio d etection a nd r anging.

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Discover More

Police use radar techniques to determine the speed of automobiles.

Other Word Forms

• antiradar noun

Etymology

Origin of radar

1940–45, ra(dio) d(etecting) a(nd) r(anging)

Compare meaning

How does radar compare to similar and commonly confused words? Explore the most common comparisons:

• sonar vs. radar

Example Sentences

Iran’s Kharg Island, which has been on Mr. Trump’s radar since the 1980s, has emerged as a tempting target.

From The Wall Street Journal • Mar. 31, 2026

She said: "It's about getting it on people's radar that these places are special and that we should be looking after them."

From BBC • Mar. 28, 2026

Is L.A. so awful for these kids that it isn’t even on their radar to stay close to home?

From Los Angeles Times • Mar. 28, 2026

Japan has installed missiles, radar, garrisons and electronic-warfare systems on the islands to protect the archipelago amid intensifying Chinese military activity in the East China Sea and—potentially—to play a role in any defense of Taiwan.

From The Wall Street Journal • Mar. 28, 2026

Meanwhile, I knew my name wasn’t even on the radar for the foundation coaches.

From "Proud" by Ibtihaj Muhammad

Related Words

• sonar