tri·ad / ˈtrīˌad/ • n. 1. a group or set of three connected people or things: the triad of medication, diet, and exercise are necessary in diabetes care. ∎  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. (also Triad) a secret society originating in China, typically involved in organized crime. ∎  a member of such a society.DERIVATIVES: tri·ad·ic / trīˈadik/ adj. (in sense 1).

triad a group or set of three connected people or things, as, a Welsh form of literary composition with an arrangement of subjects or statements in groups of three.

The name Triad is used for a secret society originating in China, typically involved in organized crime; it comes from Chinese San Ho Hui, literally ‘triple union society’, which was said to mean ‘the union of Heaven, Earth, and Man’. The original society was formed in the early 18th century, with the alleged purpose of ousting the Manchu dynasty.

triad Chinese secret society. It existed in s China from the earliest days of the Qing Empire in the 17th century until the 19th century, when the triads lent their support to the Taiping Rebellion. Today, it is said to control Chinese organized crime around the world, with its chief centre in Hong Kong.

triad. Chord of 3 notes, basically a ‘root’ and the notes a third and a fifth above it, forming two superimposed thirds, e.g. C–E–G (‘common chord’ of C major). If lower third is major and the upper minor, the triad is major. If lower third is minor and the upper major, the triad is minor. If both are major the triad is augmented. If both are minor, the triad is diminished.

triad A triad, or three-person group, is often the least stable of small groups, as there is a tendency for triads to divide into a dyad and an isolate. Two weaker members may form a coalition against the stronger third, or the weakest member may gain power by dividing the other two.