A typical Petrarchan sonnet is a 14-line poem written in iambic pentameter. It is separated into two stanzas, the octave, and the sestet. The octave is an eight-line opener, which proposes a problem. The sestet is a six-line closer, which comments on the problem introduced in the octave.
Iambic pentameter employs one of many rhyme schemes and adheres to a tightly structured thematic organization. Two sonnet forms provide the models from which all other sonnets are formed: the Petrarchan and the Shakespearean.
The structure of the Petrarchan establishes the structure became known as the Shakespearean sonnet. This structure has been adapted to lend itself much better to the comparatively rhyme poor English language.