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  1. the coiled, chambered fossil shell of an ammonoid.

Origin of ammonite1

1700–10; < New Latin Ammonites < Medieval Latin (cornū) Ammōn(is) (literally, horn of Ammon) + -ītes -ite1; fossil so called from its resemblance to the horn of Jupiter Ammon
Related formsam·mo·nit·ic [am-uh-nit-ik] /ˌæm əˈnɪt ɪk/, adjectiveam·mon·i·toid [uh-mon-i-toid] /əˈmɒn ɪˌtɔɪd/, adjective


  1. a nitrogenous mixture consisting chiefly of dried animal fats, usually obtained from livestock carcasses, and used as a fertilizer.

Origin of ammonite2

First recorded in 1600–10; ammo(nium) + nit(rat)e


  1. an inhabitant of Ammon.
  1. of or relating to the Ammonites.

Origin of Ammonite

First recorded in 1605–15; Ammon + -ite1
Related formsAm·mon·it·ish, adjectivepre-Am·mon·ite, adjective, noun
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018

Examples from the Web for ammonites

Historical Examples

  • The Ammonites also paid tribute to Uzziah, for he became very strong.

    The Children's Bible

    Henry A. Sherman

  • When was it ever known that the Ammonites proved wanting to their own interests?

  • He, after this, overthrew the Ammonites, and appointed that they should pay tribute.

  • And when he had done this, he came to the king of the Ammonites.

  • It was in the Jurassic that the Ammonites reached their height.

    The Elements of Geology

    William Harmon Norton

British Dictionary definitions for ammonites


pl n
  1. Old Testament a nomadic tribe living east of the Jordan: a persistent enemy of the Israelites


  1. any extinct marine cephalopod mollusc of the order Ammonoidea, which were common in Mesozoic times and generally had a coiled partitioned shell. Their closest modern relative is the pearly nautilus
  2. the shell of any of these animals, commonly occurring as a fossil
Derived Formsammonitic (ˌæməˈnɪtɪk), adjective

Word Origin

C18: from New Latin Ammōnītēs, from Medieval Latin cornū Ammōnis, literally: horn of Ammon


  1. an explosive consisting mainly of ammonium nitrate with smaller amounts of other substances, such as TNT
  2. a nitrogenous fertilizer made from animal wastes

Word Origin

C20: from ammo (nium) + ni (tra) te
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 ammonites



"cephalopod mollusk," 1758, from French (Breyn, 1732), "better established" [Century Dictionary] by French zoologist Jean Guillaume Bruguière (c.1750-1798) in 1789, from Medieval Latin (cornu) Ammonis "horn of Ammon," the Egyptian god of life and reproduction, who was depicted with ram's horns, which the fossils resemble. The resemblance also was noted in ancient times.

Online Etymology Dictionary, © 2010 Douglas Harper

ammonites in Science


  1. Any of the ammonoids belonging to the order Ammonitida and living during the Jurassic and the Cretaceous Periods. Ammonites had a thick, very ornamental chambered shell with highly defined, wavy sutures between the chambers.
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.