ammonoid

 
Pronunciation: /ˈamənɔɪd/
Palaeontology

noun

  • an extinct cephalopod mollusc with a flat-coiled spiral shell, found commonly as a fossil in marine deposits from the Devonian to the Cretaceous periods.

adjective

  • relating to the ammonoids.

Origin:

mid 19th century: from modern Latin Ammonoidea, based on Ammon (see ammonite)