- A prefix (also used adjectively) denoting three proportional or combining part or the third degree of that to the name of which it is prefixed; as in trisulphide, trioxide, trichloride.
- A prefix meaning three, thrice, threefold; as in tricolored, tridentate.
Webster's Revised Unabridged Dictionary
| APA | Webster's. (2011). tri-. Retrieved September 22, 2026, from http://smartdefine.org/tri-/definitions/2074445 |
| Chicago | Webster's. 2011. "tri-" http://smartdefine.org/tri-/definitions/2074445 (accessed September 22, 2026). |
| Harvard | Webster's 2011, tri-, Smart Define, viewed 22 September, 2026, <http://smartdefine.org/tri-/definitions/2074445>. |
| MLA | Webster's. "tri-" 28 May 2011. Web. 22 September 2026. <http://smartdefine.org/tri-/definitions/2074445> |