Diptych

Diptych (/ˈdɪptɪk/; is from the Greek δίπτυχον, di "two" + ptychē "fold") is any object with two flat plates which form a pair, often attached by hinge. For example, the standard notebook and school exercise book of the ancient world was a diptych consisting of a pair of such plates that contained a recessed space filled with wax. Writing was accomplished by scratching the wax surface with a stylus. When the notes were no longer needed, the wax could be slightly heated and then smoothed to allow reuse. Ordinary versions had wooden frames, but more luxurious diptychs were crafted with more expensive materials.

Diptych can also refer to two paintings that are joined together.

Conrad von Soest: St. Dorothea (diptych), c. 1420. Westphalian State Museum, Münster

Conrad von Soest, St. Odilia (diptych), c. 1420. Westphalian State Museum, Münster

Stefan Lochner: Adoration of the Christ Child by the Virgin (The Nativity) (diptych), c. 1445s. Alte Pinakothek, Münich

Stefan Lochner, Presentation at the Temple (diptych), c. 1447 Calouste Gulbenkian Museum, Lisbon