Hardhead \Hard"head`\, n. 1. Clash or collision of heads in contest. --Dryden. 2. (Zo["o]l.) (a) The menhaden. See {Menhaden}. [Local, U.S.] (b) Block's gurnard ({Trigla gurnardus}) of Europe. (c) A California salmon; the steelhead. (d) The gray whale. See {Gray whale}, under {Gray}. (e) A coarse American commercial sponge ({Spongia dura}).