hammerhead (plural hammerheads)
- The portion of a hammer containing the metal striking face (also including the claw or peen if so equipped).
- (zoology) Any of various sharks of the genus Sphyrna or Zygaena having the eyes set on projections from the sides of the head, which gives it a hammer shape.
- (zoology) A fresh-water fish; the stone-roller, in the minnow family Cyprinidae.
- (zoology) An African fruit bat, the hammer-headed fruit bat, Hypsignathus monstrosus, so called from its large blunt nozzle.
- (slang) A stupid person, a dunce.
- 1960: [The butler] joined us with a telegram for Bobbie on a salver. From her mother, I presumed, calling me some name which she had forgotten to insert in previous communications. Or, of course, possibly expressing once more her conviction that I was a guffin, which, I thought, having had time to ponder over it, would be something in the nature of a bohunkus or a hammerhead. (P. G. Wodehouse, Jeeves in the Offing, chapter V)
- (biology) A kind of ribozyme; hammerhead ribozyme.