ottava rima(n = noun.communication) - a stanza of eight lines of heroic verse with the rhyme scheme abababcc;
is a kind of stanza

   A stanza of eight lines of heroic verse, with three rhymes, the first six lines rhyming alternately and the last two forming a couplet. It was used by Byron in “Don Juan,” by Keats in “Isabella,” by Shelley in “The Witch of Atlas,” etc. [Webster 1913 Suppl.]

ottava rima, n. a stanza of eight lines of 10 or 11 syllables, rhyming abababcc.

Etymology:
It., lit. eighth rhyme

rima, rima glottidis, rima oris, rima pudendi, rima respiratoria, rima vestibuli, rima vocalis, rima vulvae, terza rima