What are the parts that make up a sonnet?

The rhyme scheme of a Petrarchan Sonnet is abbaabbacdcdcd. In a Petrarchan or Italian Sonnet, the first eight lines are related. Line 9 is called "the turn", signifying a change in rhyme pattern and a change in subject matter. Each line of a sonnet consists of 10 syllables following a pattern of unstressed syllable, stressed syllable (each pair is an "iamb").