• synonyms


  1. the part of a hammer designed for striking.
  2. a shark of the genus Sphyrna, especially S. zygaena, having the head expanded laterally so as to resemble a double-headed hammer, sometimes dangerous to swimmers.
  3. Also called ham·mer·kop [ham-er-kop] /ˈhæm ərˌkɒp/. a brown heronlike African bird, Scopus umbretta, having the head so crested as to resemble a claw hammer.
  4. flatheaded borer.
  5. Slang. blockhead; dunce; lout.
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Origin of hammerhead

First recorded in 1525–35; hammer + head
Related formsham·mer·head·ed, adjective
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018

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British Dictionary definitions for hammerhead


  1. any shark of the genus Sphyrna and family Sphyrnidae, having a flattened hammer-shaped head
  2. a heavily built tropical African wading bird, Scopus umbretta, related to the herons, having a dark plumage and a long backward-pointing crest: family Scopidae, order Ciconiiformes
  3. a large African fruit bat, Hypsignathus monstrosus, with a large square head and hammer-shaped muzzle
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Derived Formshammerheaded, adjective
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Word Origin and History for hammerhead


type of shark, 1843, from hammer (n.) + head (n.). So called for its broad, transverse head.

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Online Etymology Dictionary, © 2010 Douglas Harper