Definition from Wiktionary, the free dictionary
- IPA: /tɹaɪ.æd/
triad (plural triads)
- A grouping of three.
- (music) A chord consisting of a root tone, the tone two degrees higher, and the tone four degrees higher in a given scale.
- (electronics) on a CRT display, a group of three neighbouring phosphor dots, coloured green, red, and blue.
- A branch of a Chinese underground criminal society, mostly based in Hong Kong.
Related terms 
grouping of three