coxswain UK /ˈkɒk.s(ə)n/US /ˈkɑk.s(ə)n/noun 4verb 1forms 3 noun4 •In a ship's boat, the helmsman given charge of the boat's crew. •The member of a crew who steers the shell and coordinates the power and rhythm of the rowers. •A rank or position.Canadian Navy Coxswain (or Capitaine d'Armes) is the senior non-commissioned officer aboard a shipBritish Royal Navy Cadets Cadet Coxswain is the highest normal rank which may be achieved. •(no longer used) The second or third mate of a vessel, in charge of the master's barge. verb1 •To act as coxswain for. formscoxswained · coxswaining · coxswains