Noun
a sonnet consisting of an octave with the rhyme pattern abbaabba, followed by a sestet with the rhyme pattern cdecde or cdcdcd
Source: WordNetFor example, when Romeo talks about Rosaline earlier in the play, he attempts to use the Petrarchan sonnet form. Source: Internet
In the Petrarchan sonnet, the turn tends to fall around the division between the first two quatrains and the sestet, while English sonnets usually place it at or near the beginning of the closing couplet. Source: Internet