(n.) A genus of pearly bivalve shells, numerous extinct species of which are characteristic of the Mesozoic rocks. A few living species exist on the coast of Australia.
Webster's Revised Unabridged Dictionary
| APA | Webster's. (2011). trigonia. Retrieved September 23, 2026, from http://smartdefine.org/trigonia/definitions/2074671 |
| Chicago | Webster's. 2011. "trigonia" http://smartdefine.org/trigonia/definitions/2074671 (accessed September 23, 2026). |
| Harvard | Webster's 2011, trigonia, Smart Define, viewed 23 September, 2026, <http://smartdefine.org/trigonia/definitions/2074671>. |
| MLA | Webster's. "trigonia" 28 May 2011. Web. 23 September 2026. <http://smartdefine.org/trigonia/definitions/2074671> |