The Collaborative International Dictionary of English v.0.48:

Adage \Ad"age\, n. [F. adage, fr. L. adagium; ad + the root of
   L. aio I say.]
   An old saying, which has obtained credit by long use; a
   proverb.
   [1913 Webster]

         Letting "I dare not" wait upon "I would,"
         Like the poor cat i' the adage.          --Shak.
   [1913 Webster]

   Syn: Axiom; maxim; aphorism; proverb; saying; saw; apothegm.
        See Axiom.
        [1913 Webster]

WordNet (r) 3.0 (2006):

adage
    n 1: a condensed but memorable saying embodying some important
         fact of experience that is taken as true by many people
         [syn: proverb, adage, saw, byword]

Moby Thesaurus II by Grady Ward, 1.0:

44 Moby Thesaurus words for "adage":
   ana, analects, aphorism, apothegm, axiom, byword, catchword,
   collected sayings, current saying, dictate, dictum, distich,
   epigram, expression, gnome, golden saying, maxim, moral, mot,
   motto, oracle, phrase, pithy saying, precept, prescript, proverb,
   proverbial saying, proverbs, saw, saying, sentence,
   sententious expression, sloka, stock saying, sutra, teaching, text,
   verse, wisdom, wisdom literature, wise saying, witticism, word,
   words of wisdom



The Devil's Dictionary (1881-1906):

ADAGE, n.  Boned wisdom for weak teeth.