sonar

Noun

1.

sonar - a measuring instrument that sends out an acoustic pulse in water and measures distances in terms of the time for the echo of the pulse to return; sonar is an acronym for sound navigation ranging; asdic is an acronym for anti-submarine detection investigation committee Synonyms: asdic, echo sounder

asdic, echo sounder, measuring device, measuring instrument, measuring system, navigational instrument, pigboat, pinger, pulse generator, sub, submarine, U-boat