- triad (n.)
[triad 词源字典]
- 1540s, "group or set of three," from Late Latin trias (genitive triadis), from Greek trias (genitive triados) "a triad, the number three," from treis "three" (see three). Musical sense of "chord of three notes" is from 1801. Related: Triadic.[triad etymology, triad origin, 英语词源]