(also called the Shakespearean sonnet
after its foremost practitioner) comprises three quatrains and a final couplet,
rhyming ababcdcdefefgg. An important variant of this is the Spenserian sonnet (introduced by
the Elizabethan poet Edmund Spenser), which links the three quatrains by rhyme,
in the sequence ababbabccdcdee. In either form, the ‘turn’ comes with
the final couplet, which may sometimes achieve the neatness of an epigram” (Baldick).