acoustic buoy(n = noun.communication) - a buoy that can be heard (at night);
is a kind of buoy
has particulars: bell buoy, gong buoy, whistle buoy, whistling buoy

acoustic, acoustic aphasia, acoustic delay line, acoustic device, acoustic gramophone, acoustic guitar, acoustic impedance, acoustic meatus, acoustic modem, acoustic nerve, acoustic phenomenon, acoustic power, acoustic projection, acoustic radiation pressure, acoustic reactance, acoustic resistance, acoustic spectrum, acoustic storage, acoustic wave, bell buoy, breeches buoy, buoy, buoy up, can buoy, conical buoy, gong buoy, life buoy, nun buoy, ship-towed long-range acoustic detection system, spar buoy, whistle buoy, whistling buoy