1570s, from Late Latin tautologia "representation of the same thing in other words," from Greek tautologia, from tautologos "repeating what has been said," from tauto "the same" (contraction of to auto, with to "the" + auto, see auto-) + -logos "saying," related to legein "to say" (see lecture (n.)). Related: Tautological.[tautology etymology, tautology origin, 英语词源]