ammonite

plural ammonites

1. biologyAny of an extinct group of cephalopods of the subclass Ammonoidea; a fossil shell of such an animal.

   There's more interest to my mind in a neolithic scraper than in a whole show-case-full of ammonites and belemnites.

   1927, Ernest Bramah [pseudonym; Ernest Brammah Smith], Max Carrados Mysteries

   2 more examples

   Ammonites floated through the world's shallow oceans for more than three hundred million years, and their fossilized shells turn up all around the world.

   2014, Elizabeth Kolbert, The Sixth Extinction: An Unnatural History, Picador, →ISBN, page 83

   There are a few well known shelled giant cephalopods from the fossil record. Some of the largest recorded ammonites are in the genus Parapuzosia, fossils of which reach up to 2m in diameter.

   2017 October 31, Mark Carnall, “Searching for the Old Ones: Lovecraftian giant cephalopods and the fossil record”, in The Guardian

   Synonyms: ammonid, ammonoid

1. uncountableAn explosive prepared from a mixture of TNT and ammonium nitrate; a form of amatol, popular in Eastern Europe and China.

plural Ammonites

1. A native or inhabitant of Ammon.

1. not comparableOf or pertaining to the Ammonites.

   Synonyms: Ammonitish

1. The extinct Canaanite language of the Ammonite people who used to live in modern-day northwest Jordan, and after whom its capital Amman is named. Extinct since 5th century BCE.