terza rima

from WordNet (r) 3.0 (2006)

terza rima
    n 1: a verse form with a rhyme scheme: aba bcb cdc, etc.

from The Collaborative International Dictionary of English v.0.48

Terza rima \Ter"za ri"ma\ [It., a third or triple rhyme.]
   A peculiar and complicated system of versification, borrowed
   by the early Italian poets from the Troubadours.
   [1913 Webster]