noun, plural ot·ta·va ri·mas.
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.
Origin of ottava rima
1810–20; < Italian: octave rhyme
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prosody a stanza form consisting of eight iambic pentameter lines, rhyming a b a b a b c c
Word Origin for ottava rima
Italian: eighth rhyme
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012
1820, Italian, "eight-lined stanza," literally "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.
Online Etymology Dictionary, © 2010 Douglas Harper