'sonar' definitions:

Definition of 'sonar'

From: WordNet
noun
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 antisubmarine detection investigation committee" [syn: sonar, echo sounder, asdic]

Synonyms of 'sonar'

From: Moby Thesaurus