Tableau en deux parties.
ETYM Latin diptycha, pl., from Greek disptyche fold; di- = dis- twice + ptyche fold.
A painting or carving (especially an altarpiece) on two panels (usually hinged like a book).
Pair of pictures on hinged panels; register of bishops and saints.
Paintings on a pair of hinged tablets used as altar-piece; pair of hinged wax writing tablets.
Painting or sculpture (usually in ivory) consisting of two panels hinged together, most often employed as a portable altar or altarpiece. The Wilton Diptych about 1395 (National Gallery, London) is an example.