Cowfish \Cow"fish`\ (-f?ch`), n. (Zo["o]l.) (a) The grampus. (b) A California dolphin ({Tursiops Gillii}). (c) A marine plectognath fish ({Ostracoin quadricorne}, and allied species), having two projections, like horns, in front; -- called also {cuckold}, {coffer fish}, {trunkfish}.