Ham″mer‐head′ (–hĕd′), n. 1. (Zoöl.) A shark of the genus Sphyrna or Zygæna, having the eyes set on projections from the sides of the head, which gives it a hammer shape. The Sphyrna zygæna is found in the North Atlantic. Called also hammer fish, and balance fish.
2. (Zoöl.) A fresh-water fish; the stone-roller.
3. (Zoöl.) An African fruit bat (Hypsignathus monstrosus); — so called from its large blunt nozzle.