Noah Webster's New International Dictionary of the English Language

1. (n.) A figure having three angles; a triangle.

2. (n.) A division consisting of three signs.

3. (n.) Trine, an aspect of two planets distant 120 degrees from each other.

4. (n.) A kind of triangular lyre or harp.

5. (n.) A kind of game at ball played by three persons standing at the angular points of a triangle.