A painting or carving (especially an altarpiece) on two panels (usually hinged like a book)

• Ancient two-leaved tablet
• Hinged pair of pictures

The Collaborative International Dictionary Word definitions in The Collaborative International Dictionary
Diptych \Dip"tych\, n. [L. diptycha, pl., fr. Gr. ? folded, doubled; di- = di`s- twice + ? to fold, double up.] Anything consisting of two leaves. Especially: (Roman Antiq.) A writing tablet consisting of two leaves of rigid material connected by hinges ...

Wiktionary Word definitions in Wiktionary
n. 1 A writing tablet consisting of two leaves of rigid material connected by hinges and shutting together so as to protect the writing within. 2 (context arts English) A picture or series of pictures painted on two tablets, usually connected by hinges. ...

WordNet Word definitions in WordNet
n. a painting or carving (especially an altarpiece) on two panels (usually hinged like a book)

Douglas Harper's Etymology Dictionary Word definitions in Douglas Harper's Etymology Dictionary
1620s, from Latin diptycha (plural), from late Greek diptykha , neuter plural of diptykhos "double-folded, doubled," from dis- "two" + ptykhe "fold."

Wikipedia Word definitions in Wikipedia
A diptych (; from the Greek δίπτυχον, di "two" + ptychē "fold") is any object with two flat plates attached at a hinge . In particular the standard notebook and school exercise book of the ancient world was the diptych consisting of a pair of such plates ...