ETYM Latin tautologia: cf. French tautologie.
1. Useless repetition.
2. (In logic) A statement that is necessarily true.
Repetition of sense of word(s) in other unnecessary words. Repetition of the same thing in different words. For example, it is tautologous to say that something is most unique, since something unique cannot, by definition, be comparative.
1. Redondance.
2. (Logique) Proposition vraie quelle que soit la vérité de ses composants.