The Collaborative International Dictionary of English v.0.48:
Headfish \Head"fish`\ (h[e^]d"f[i^]sh`), n. (Zool.) The sunfish (Mola). Head gearWordNet (r) 3.0 (2006):
headfish n 1: among the largest bony fish; pelagic fish having an oval compressed body with high dorsal and anal fins and caudal fin reduced to a rudder-like lobe; worldwide in warm waters [syn: ocean sunfish, sunfish, mola, headfish]