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 forms
ammonitic (ˌæməˈnɪtɪk)
adjective
Word origin
C18: from New Latin Ammōnītēs, from Medieval Latin cornū Ammōnis, literally: horn of Ammon
ammonite in British English2
(ˈæməˌnaɪt)
noun
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
ammonite in American English
(ˈæməˌnaɪt)
noun
any of the flat, usually coiled fossil shells of an extinct order (Ammonoidea) ofcephalopod mollusks dominant in the Mesozoic era
Derived forms
ammonitic (ˌammoˈnitic) (ˈæməˈnɪtɪk)
adjective
Word origin
ModL ammonites < L (cornu) Ammonis, (horn) of Ammon < Jupiter Ammon1, whose statues were represented with ram's horns
Examples of 'ammonite' in a sentence
ammonite
In the excitement, he fell over a large ammonite and burnt both his hands in the fire.