Английский Этимологический словарь - indent (v.)

- 14c., from O.Fr. endenter "to notch or dent, give a serrated edge to," from L.L. indentare "to crunch," from L. in- "in" + dens (gen. dentis) "tooth." The noun is first recorded 1596 from the verb. Extended form indentation first recorded 1728. Indenture "contract for services," is early 14c., from Anglo-Fr. endenture, from O.Fr. endenteure "indentation," from endenter. 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.