triad [M16th] Triad meaning ‘set of three’ goes back to Greek tres ‘three’. The Chinese secret societies are called Triads [E19th] from their Chinese name San Ho Hui which can be translated as ‘triple union society’. Triangle [LME] comes from the same word. The eternal triangle of romance dates from the early 20th century. Trinitas is the Latin for ‘triad’ and the source of trinity [ME]. The musical trio [E18th] comes from the Italian development of tres. Triple [ME] is from the same root; and tripod [LME] is a three-footed device, from tri- ‘three’ podes ‘feet’. Trivet [LME] comes from the Latin form of the word.