The Collaborative International Dictionary of English v.0.48:
Assonate \As"so*nate\, v. i. [L. assonare, assonatum, to respond to.] To correspond in sound. [1913 Webster]WordNet (r) 3.0 (2006):
assonate v 1: correspond in vowel sounds; rhyme in assonance; "The accented vowels assonated in this poem"