indenture (n.)
"contract for services," late 14c., from Anglo-French endenture, Old French endenteure "indentation," from endenter (see indent). Such contracts (especially between master craftsmen and apprentices) were written in full identical versions on a sheet of parchment, which was then cut apart in a zigzag, or "notched" line. Each party took one, and the genuineness of a document of indenture could be proved by juxtaposition with its counterpart. As a verb, 1650s, from the noun.