Quiz: Remember the definition of mal de mer?
early 15c., indenten/endenten "to make notches; to give (something) a toothed or jagged appearance," also "to make a legal indenture," from Old French endenter "to notch or dent, give a serrated edge to," from Medieval Latin indentare "to furnish with teeth," from in- "into, in, on, upon" (see in- (2)) + Latin dens (genitive dentis) "tooth" (see tooth). Related: Indented; indenting. The printing sense is first attested 1670s. The noun is first recorded 1590s, from the verb. An earlier noun sense of "a written agreement" (late 15c.) is described in Middle English Dictionary as "scribal abbrev. of endenture."