radar

noun

ra·​dar ˈrā-ˌdär How to pronounce radar (audio)
often attributive
1
: a device or system consisting usually of a synchronized radio transmitter and receiver that emits radio waves and processes their reflections for display and is used especially for detecting and locating objects (such as aircraft) or surface features (as of a planet)
2
: range of notice
fell off the radar after losing their first three games

Examples of radar in a Sentence

The approaching planes were detected by radar.
Recent Examples on the Web
Examples are automatically compiled from online sources to show current usage. Read More Opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback.
Additional sensors, including radar and passive radio-frequency detection equipment, can provide information to help cue the weapon toward potential threats. — Prabhat Ranjan Mishra, Interesting Engineering, 16 Oct. 2026 Parts of this are relatively localized radar towers and ground systems. — Gerard Toal, The Conversation, 16 Oct. 2026 Romania’s acting defense minister, Radu Miruta, said that an investigation was underway, but that no drone was seen on military radars heading toward that tanker. — Los Angeles Times, 15 Oct. 2026 On Friday, Marshall toured a radar manufacturing plant with Transportation Secretary Sean Duffy. — ABC News, 15 Oct. 2026 See All Example Sentences for radar

Word History

Etymology

radio detecting and ranging

First Known Use

1941, in the meaning defined at sense 1

Time Traveler
The first known use of radar was in 1941

Phrases Containing radar

Rhymes for radar

See All Rhymes for radar

Browse Nearby Words

rad
radar
radar astronomy
See all Nearby Words

Cite this Entry

“Radar.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/radar. Accessed 20 Oct. 2026.

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Kids Definition

radar

noun
ra·​dar ˈrā-ˌdär How to pronounce radar (audio)
: a device that sends out radio waves for detecting and locating an object by the reflection of the radio waves and that may use this reflection to find out the position and speed of the object
Etymology

from radio detecting and ranging

More from Merriam-Webster on radar

Britannica.com: Encyclopedia article about radar

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