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ammonoid
[ am-uh-noid ]
noun
- any cephalopod mollusk of the extinct order Ammonoidea, from the Devonian to the Cretaceous periods, having a coiled, chambered shell.
ammonoid
/ ăm′ə-noid′ /
- Any of various extinct cephalopods of the subclass Ammonoidea living from the Devonian to the Cretaceous Periods. Ammonoids had a symmetrical, coiled, chambered shell with angular sutures between the chambers. They are closely related to the nautiloids, including the modern-day chambered nautilus.
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Word History and Origins
Origin of ammonoid1
1880–85; < New Latin Ammonoidea, equivalent to Ammon ( ites ) name of the order + -oidea -oidea; ammonite 2
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