2.GROUP OF PEOPLEGROUP OF THINGSa group of three people or things that are related or similar to each other 三人组合；三种事物的组合
Examples from the Corpus
triad• But other alleged triad leaders used violence to muscle their way into the business, according to the police.• Behind him are three priests representing the male triad.• The secondary triad comprises a rival agent, a vicious hit-man for the opposition and a series of pretty girls.• The Hong Kong police special triad squad responded with pressure of its own, according to McNicol.• This has the effect of rounding the contours and losing some of the austerity of the unadorned triads.
Origintriad
(1500-1600)Frenchtriade, from Latin, from Greek, from treis“three”