ETYM Latin, from res, gen. trium, three + vir a man. Related to Three, and Virile.
One of a group of three sharing public administration or civil authority especially in ancient Rome.
Member of triumvirate.
One of a group of three administrators sharing power in ancient Rome, as in the First Triumvirate 60 bc: Caesar, Pompey, Crassus; and Second Triumvirate 43 bc: Augustus, Antony, and Lepidus.