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

The two countries also established a vast radar system to monitor possible missile attacks over the Arctic. — Robert B. Zoellick, Foreign Affairs, 9 Oct. 2026

Gallium is particularly important to the defense industry as it is used to produce specialized semiconductors found in advanced radar systems, electronic warfare equipment, and military communications technology. — Georgina Jedikovska, Interesting Engineering, 9 Oct. 2026

These six episodes are a pleasant surprise, offering more than what initially appeared on the surface, but the story wouldn’t be able to operate below the radar a second time. — Daniel Fienberg, HollywoodReporter, 8 Oct. 2026

During the famed 1969 Apollo 11 mission, Hamilton’s software overrode an errant attempt to swap the flight computer’s primary processing to a radar system. — Jackie Wattles, CNN Money, 8 Oct. 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