triad

noun6

1. •
   A grouping of three.

   • Later artworks showed many animals and gods, some of which were clearly identified with heavenly body. They often included the symbolic triad of Sun, Moon, and Venus. — 1998
2. •
   A romantic or sexual relationship between three individuals; a throuple.
3. •
   On a CRT display, a group of three neighbouring phosphor dots, coloured green, red, and blue.
4. •
   A branch of a Chinese underground criminal society, mostly based in Hong Kong.
5. •
   A chord consisting of a root tone, the tone two degrees higher, and the tone four degrees higher in a given scale OR any chord with three notes.
6. •
   A word of three syllables.