(n.) An extinct genus of Paleozoic Cephalopoda, having a long, straight, conical shell. The interior is divided into numerous chambers by transverse septa.
Webster's Revised Unabridged Dictionary
| APA | Webster's. (2011). Orthoceras. Retrieved September 24, 2026, from http://smartdefine.org/orthoceras/definitions/2039558 |
| Chicago | Webster's. 2011. "Orthoceras" http://smartdefine.org/orthoceras/definitions/2039558 (accessed September 24, 2026). |
| Harvard | Webster's 2011, Orthoceras, Smart Define, viewed 24 September, 2026, <http://smartdefine.org/orthoceras/definitions/2039558>. |
| MLA | Webster's. "Orthoceras" 27 May 2011. Web. 24 September 2026. <http://smartdefine.org/orthoceras/definitions/2039558> |