triad
Word family nountriadtriadist
tri·ad /ˈtraɪæd/ noun [countableC] 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 Origin triad (1500-1600) French triade, from Latin, from Greek, from treis “three”