Orthoceras

noun
Or·​thoc·​er·​as | \ȯ(r)ˈthäsərəs\

Definition of Orthoceras 

: an ill-defined genus of extinct nautiloid cephalopod mollusks having a long tapering shell that is nearly or quite straight, almost smooth, and many-chambered

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History and Etymology for Orthoceras

New Latin, from orth- + -ceras

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