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"
without deviation; "the path leads directly to the lake"; "went direct to the office"
in a forthright manner; candidly or frankly; "he didn't answer directly"; "told me straight out"; "came out flat for less work and more pay"
without anyone or anything intervening; "these two factors are directly related"; "he was directly responsible"; "measured the physical properties directly"