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"
echolocation
"The submarine used sonar to detect the school of fish swimming ahead without revealing its own position."
Acronym of sound navigation and ranging.
The word sonar is derived from the acronym SOund Navigation And Ranging, which was originally used as a technical term before evolving into standard English usage. It does not have a traditional root meaning but rather represents the initial letters of its descriptive phrase.