(n.) An extinct genus of Brachiopoda, abundant in the Paleozoic rocks.
Webster's Revised Unabridged Dictionary
| APA | Webster's. (2011). orthis. Retrieved September 23, 2026, from http://smartdefine.org/orthis/definitions/2039553 |
| Chicago | Webster's. 2011. "orthis" http://smartdefine.org/orthis/definitions/2039553 (accessed September 23, 2026). |
| Harvard | Webster's 2011, orthis, Smart Define, viewed 23 September, 2026, <http://smartdefine.org/orthis/definitions/2039553>. |
| MLA | Webster's. "orthis" 27 May 2011. Web. 23 September 2026. <http://smartdefine.org/orthis/definitions/2039553> |