Characteristics of All Sonnets
All sonnets have the following three features in common: They are 14 lines long, have a regular rhyme scheme and a strict metrical construction, usually iambic pentameter. Iambic pentameter means that each line has 10 syllables in five pairs, and that each pair has stress on the second syllable.
Shakespearean sonnets, named after William Shakespeare, have the following rhyme scheme: abab, cdcd, efef, gg. It is divided into three quatrains, or four lines -- the first of which is abab -- and one concluding couplet -- gg. The first line in the first quatrain rhymes with the third line; both are "a"; the second line rhymes with the fourth, which are both "b."
Spenserian sonnets, named after Edmund Spenser, like Shakespearean sonnets, are divided into three quatrains and a couplet. But the rhyme scheme is different; it is abab, bcbc, cdcd, ee.
Petrarch sonnets, named after Francesco Petrarcas, have two quatrains and two tercets, which are three-line stanzas. The rhyme scheme is usually abba, abba, cde, cde.