How do you spell Trigon

Available Definitions:
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.