diptych

A writing tablet consisting of two leaves of rigid material connected by hinges and shutting together so as to protect the writing within.

A picture or series of pictures painted on two tablets, usually connected by hinges.

双联画

A double catalogue, containing in one part the names of living, and in the other of deceased, ecclesiastics and benefactors of a church.

A catalogue of saints.

A novel published in two volumes forming one continuous story (as opposed to a duology or dilogy).

A literary work consisting of two contrasting parts, such as a narrative telling the same story from two opposing points of view.

Any work made up of two parts treating complementary or contrasting aspects of one general topic.

Artistically-wrought tablets distributed by consuls, etc. of the later Roman Empire to commemorate their tenure of office; hence (transferred sense) a list of magistrates.