a fourteen-line poem in iambic pentameter comprised of an octave to a sestet and rhyming in some variation of abbaabbacdecde.
a sonnet consisting of an octave with the rhyme pattern abbaabba, followed by a sestet with the rhyme pattern cdecde or cdcdcd
The oldest form of the sonnet is the Italian or Petrarchan Sonnet (named for its greatest practitioner—Petrarch). Its rhyme scheme is usually an octave (eight lines) and a sestet (six lines). The octave usually follows a pattern of abbaabba. The concluding sestet may be cdecde or cdcdcd or cdedce.