"repetition of the same word, or use of several words conveying the same idea, in the same immediate context; repetition of the same thing in different words; the useless repetition of the same idea or meaning" (as in they arrived simultaneously at the same time); 1570s, from Late Latin tautologia "representation of the same thing in other words," from Greek tautologia, from tautologos "repeating what has been said." This is a compound of tauto "the same" (see tauto-) + -logos "saying" (see Logos)." Related: Tautological; tautologically; tautologous; tautologize. Tautology is repetition without addition of force or clearness, and is disguised by a change of wording ; it differs from the repetition which is used for clearness, emphasis, or effect, and which may be either in the same or in different words [Century Dictionary]