What is a work of art set on three panels hinged together which may be used as an altarpiece?

A work of art set on three panels hinged together, often used as an altarpiece, is known as a triptych. Triptychs are typically painted or carved and can depict religious scenes, narratives, or themes. The central panel is usually larger and more prominent, while the side panels complement the main image, enhancing the overall composition and meaning of the artwork. These pieces were commonly used in churches during the medieval and Renaissance periods.