Sonar

How to spell sonar

5 letters · 2 syllables

How to pronounce sonar

Say the part in capitals loudest.

What does sonar mean?

1. nounA system that detects and locates underwater objects by sending out sound pulses and measuring their echoes.

Sonar in a sentence

• The submarine used sonar to map the ocean floor.

• The fishing boat was fitted with sonar to find shoals beneath the surface.

Where does sonar come from?

Language of origin: Other

Sonar is a twentieth-century acronym, coined in the United States during the 1940s from the phrase 'sound navigation and ranging'. It was modelled deliberately on the slightly older British term 'asdic' and on 'radar' (radio detection and ranging), all of which describe systems that locate distant objects by bouncing a signal off them and timing the echo. In the case of sonar the signal is sound: a pulse is sent through water, and the time it takes to return reveals how far away a submarine, shoal of fish, or seabed feature lies. Because the word is built from initial letters of ordinary English words rather than from a Latin or Greek root, its spelling is phonetic and regular, and it quickly passed from naval jargon into general use. The same echo-locating idea later gave its name to the natural sonar used by bats and dolphins.

How the word is built

• so- (sound)
• na- (navigation and)
• r (ranging); an acronym formed from 'sound navigation and ranging'