an Italian stanza of eight lines, each of eleven syllables (or, in the English adaptation, of ten or eleven syllables), the first six lines rhyming alternately and the last two forming a couplet with a different rhyme: used in Keats' Isabella and Byron's Don Juan.
1820, from It., "eight-lined stanza," lit. "eighth rhyme," from ottava "eighth" (see octave). A stanza of eight 11-syllable lines, rhymed a b a b a b c c, but in the Byronic variety, they are English heroic lines of 10 syllables.