Word Study
Belemnite
CIDE DICTIONARY
Belemnite, n. [Gr. dart, fr. dart, fr. to throw: cf. F. bélemnite.].
A conical calcareous fossil, tapering to a point at the lower extremity, with a conical cavity at the other end, where it is ordinarily broken; but when perfect it contains a small chambered cone, called the phragmocone, prolonged, on one side, into a delicate concave blade; the thunderstone. It is the internal shell of a cephalopod related to the sepia, and belonging to an extinct family. The belemnites are found in rocks of the Jurassic and Cretaceous ages. [1913 Webster]
OXFORD DICTIONARY
Belemnite, n. any extinct cephalopod of the order Belemnoidea, having a bullet-shaped internal shell often found in fossilized form.
Etymology
mod.L belemnites f. Gk belemnon dart + -ITE(1)
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