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"
any collection of valuables that is discovered; "her book was a treasure trove of new ideas"; "mother's attic was a treasure trove when we were looking for antiques"
treasure of unknown ownership found hidden (usually in the earth)