Source : Webster's Revised Unabridged Dictionary (1913)

Consonance \Con"so*nance\, Consonancy \Con"so*nan*cy\, n. [L.
   consonantia: cf. F. consonnance.]
   1. (Mus.) Accord or agreement of sounds produced
      simultaneously, as a note with its third, fifth, and
      eighth.

   2. Agreement or congruity; harmony; accord; consistency;
      suitableness.

            The perfect consonancy of our persecuted church to
            the doctrines of Scripture and antiquity. --Hammond.

            The optic nerve responds to the waves with which it
            is in consonance.                     --Tyndall.

   3. Friendship; concord. [Obs.]

            By the consonancy of our youth.       --Shak.

   Syn: Agreement; accord; consistency; unison; harmony;
        congruity; suitableness; agreeableness.

Source : WordNet®

consonance
     n 1: the repetition of consonants (or consonant patterns)
          especially at the ends of words [syn: {consonant rhyme}]
     2: the property of sounding harmonious [syn: {harmoniousness}]