D defs.my
Entry 1 sense Webster, 1913

Orthoceras

· Or·thoc·e·ras · IPA
01 n. An extinct genus of Paleozoic Cephalopoda, having a long, straight, conical shell. The interior is divided into numerous chambers by trans…
  1. 1.
    An extinct genus of Paleozoic Cephalopoda, having a long, straight, conical shell. The interior is divided into numerous chambers by transverse septa.(Paleon.)