belemnite
Concise Oxford English Dictionary © 2008 Oxford University Press:
belemnite /ˈbɛləmnʌɪt/
▶noun an extinct marine cephalopod mollusc with a bullet-shaped internal shell, typically found as fossils in deposits of the Jurassic and Cretaceous periods.
– origin C17: from mod. L. belemnites, based on Gk belemnon ‘dart’.
'belemnite' also found in these Oxford entries:

