triptych
/ˈtrɪptɪk/noun
1- a picture or relief carving on three panels, typically hinged together vertically and used as an altarpiece三拼画（由三块用铰链纵向连接的画板拼成的画或浮雕, 用作圣坛装饰）, 三拼浮雕。
1.1
- a set of three associated artistic, literary, or musical works intended to be appreciated together（艺术、文学或音乐作品的）三件套（指宜完整地欣赏的三件相关作品）。
词源
mid 18th cent. (denoting a set of three writing tablets hinged or tied together)： from TRI- 'three', on the pattern of diptych.