noun
three highest ranks; top three offices
Used collectively for a set of three senior ranks or posts. In sumo it commonly refers to the titled ranks such as 大関, 関脇, and 小結; in organizations it can refer to the top three officers.
若い力士が三役に昇進した。
A young sumo wrestler was promoted to the sanyaku ranks.
組合の三役が会議に出席した。
The union's three top officers attended the meeting.
noun
three roles; three parts; three divisions
Refers to three roles, parts, or divisions taken together, especially when one person or project covers three distinct functions.
彼はこの映画で監督・脚本・主演の三役を務めた。
He handled the three roles of director, screenwriter, and lead actor in this film.
彼女は舞台で一人三役を演じた。
She played three parts by herself on stage.
A Sino-Japanese compound of 三, meaning 'three', and 役, meaning 'role, office, duty, or rank'. The spelling transparently reflects the modern meanings; the detailed historical development is not specified.