The repetition of vowel sounds in a passage.  Hamilton is ripe with assonance.  Assonance in contemporary (hip-hop) music can function similarly to internal rhymes, allowing words to resonate against each other.  See, for instance, for instance at all the ten trisyllable words from “Right Hand Man” (Hamilton) which have vowels similar to “elephant” in the following:

The venerated Virginian veteran whose men are all
Lining up, to put me up on a pedestal
Writin’ letters to relatives
Embellishin’ my elegance and eloquence
But the elephant is in the room