triumvirate

noun

• 1(in ancient Rome) a group of three men holding power, in particular ( the First Triumvirate) the unofficial coalition of Julius Caesar, Pompey, and Crassus in 60 bc and ( the Second Triumvirate) a coalition formed by Antony, Lepidus, and Octavian in 43 bc.
• a group of three powerful or notable people or things existing in relation to each other:a triumvirate of three former executive vice presidents

• 2the office of triumvir in ancient Rome.