A triptych (/ˈtrɪptɪk/ TRIP-tik; from the Greek adjective τρίπτυχον “triptukhon” (“three-fold”), from tri, i.e., “three” and ptysso, i.e., “to fold” or ptyx, i.e., “fold”)[1][2] is a work of art (usually a panel painting) that is divided into three sections, or three carved panels that are hinged together and can be folded shut or displayed open. It is therefore a type of polyptych, the term for all multi-panel works. The middle panel is typically the largest and it is flanked by two smaller related works, although there are triptychs of equal-sized panels. The form can also be used for pendant jewelry.
Despite its connection to an art format, the term is sometimes used more generally to connote anything with three parts, particularly if they are integrated into a single unit.[3]
By Heronimus Bosch, Museo del Prado., Public Domain, Link