ottava rima

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun A stanza of verse consisting of eight lines in iambic pentameter rhyming abababcc.

from The Century Dictionary.

• noun An Italian form of versification consisting of eight lines, of which the first six rime alternately and the last two form a couplet, the lines being in the proper Italian meter, the heroic of eleven syllables. Byron employed it in his “Beppo” and “Don Juan,” using lines of eleven or often of ten syllables.

from the GNU version of the Collaborative International Dictionary of English.

• (Pros.) 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.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun a stanza of eight lines of heroic verse with the rhyme scheme abababcc