Source : Webster's Revised Unabridged Dictionary (1913)

Assonant \As"so*nant\, a. [L. assonans, p. pr. of assonare to
   sound to, to correspond to in sound; ad + sonare to sound,
   sonus sound: cf. F. assonant. See {Sound}.]
   1. Having a resemblance of sounds.

   2. (Pros.) Pertaining to the peculiar species of rhyme called
      assonance; not consonant.

Source : WordNet®

assonant
     adj 1: having the same sound (especially the same vowel sound)
            occurring in successive stressed syllables; "note the
            assonant words and syllables in `tilting at
            windmills'"
     2: having the same vowel sound occurring with different
        consonants in successive words or stressed syllables