radar

noun

ra·​dar ˈrā-ˌdär 

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

Cape Newenham is part of a network of remote radar sites that monitors aircraft operating in Alaska’s airspace and along its borders. — Stephen Sorace, FOXNews.com, 25 Aug. 2026

And Delap, who has been on Forest’s radar for several weeks, ticks a lot of similar boxes, as well as a few more besides. — David Ornstein, New York Times, 25 Aug. 2026

That plane had apparently left Moscow on Tuesday afternoon, according to flight radar data. — Matthew Mulligan, NBC news, 25 Aug. 2026

Ayrshire doesn’t get the headlines or rapturous odes that the Highlands do, but this rugged coastal stretch in southwestern Scotland is filled with under-the-radar gems like Glenapp Castle. — Condé Nast, Condé Nast Traveler, 25 Aug. 2026

Word History

Etymology

radio detecting and ranging

First Known Use

1941, in the meaning defined at sense 1

Phrases Containing radar

• anti-radar
• Doppler radar
• fall off the radar
• on someone's radar (screen)
• radar astronomy
• radar beacon
• radar cruise control
• radar detector
• radar gun
• under the radar

Rhymes for radar

• adar
• afar
• ajar
• alar
• alvar
• bazaar
• bizarre
• boxcar
• boyar
• bulbar
• cachar
• cigar

Kids Definition

radar

noun

ra·​dar ˈrā-ˌdär 

: 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