noun

radar

RAY-dar/ˈreɪdɑːr/

A system for detecting objects by reflected radio signals.

The radar detects a distant aircraft and displays a corresponding blip.

A radar installation with its directional antenna aimed toward a distant aircraft and a connected circular radar display showing a corresponding target blip.

Etymology

raEnglishradio waves

+dEnglishdiscover or locate

+aEnglishand

+rEnglishdetermine distance

The name compresses “radio detecting and ranging” into an approximate acronym: radio waves are used both to detect objects and to establish how far away they are.

In context

Viking.TV22:10

is using the antennae below the wings of aircraft to project a a radar signal down through the air and then through the ice itself

Anne Diamond unlocks the mysteries of the ice with glaciologist Julian Dowdeswell

More examples

The ship uses radar to navigate through thick fog.
Weather radar shows heavy rain moving toward the coast.
Police use radar to measure the speed of passing cars.

Forms

radar · radars

Similar words

sonar: Detects objects with sound waves rather than radio waves.
lidar: Measures distances with laser light rather than radio waves.