The Collaborative International Dictionary of English v.0.48:
Tautological \Tau`to*log"ic*al\, a. [Cf. F. tautologique.] Involving tautology; having the same signification; as, tautological expression. -- Tau`to*log"ic*al*ly, adv. [1913 Webster] Tautological echo, an echo that repeats the same sound or syllable many times. [1913 Webster]