['tr??ad]
¦ noun
1. a group or set of three connected people or things.
a chord of three musical notes, consisting of a given note with the third and fifth above it.
a Welsh form of literary composition with an arrangement of subjects or statements in groups of three.
2. a Chinese secret society involved in organized crime.
a member of such a society.
Derivatives
triadic adjective
Origin
C16: from Fr. triade, or via late L. from Gk trias, triad-, from treis 'three'.