Hammerhead (-h&ebreve_;d), 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.
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2. (Zoöl.) A fresh-water fish; the stone-roller.
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3. (Zoöl.) An African fruit bat (Hypsignathus monstrosus); -- so called from its large blunt nozzle.
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