Definition of: trigon

(trī′gon) noun
1. A triangle; especially, the triangle of reference used in trilinear coordinates.
2. One of four parts of the zodiac, each consisting of three signs.
3. In Greek and Roman antiquity, a lyre or harp of triangular form. [<L trigonum <Gk. trigōnon, orig. neut. of trigōnos three–angled <tri- three + gōnia an angle]