(n.) A fossil echinus of the genus Cannulus; -- so called from its supposed resemblance to a cap.
Webster's Revised Unabridged Dictionary
| APA | Webster's. (2011). capstone. Retrieved September 20, 2026, from http://smartdefine.org/capstone/definitions/1984585 |
| Chicago | Webster's. 2011. "capstone" http://smartdefine.org/capstone/definitions/1984585 (accessed September 20, 2026). |
| Harvard | Webster's 2011, capstone, Smart Define, viewed 20 September, 2026, <http://smartdefine.org/capstone/definitions/1984585>. |
| MLA | Webster's. "capstone" 27 May 2011. Web. 20 September 2026. <http://smartdefine.org/capstone/definitions/1984585> |