What Is the Structure of a Sonnet?

A sonnet is a fourteen line poem in iambic pentameter with a volta, or thematic turn. The specific structure of a sonnet varies depending on its style, which can include Petrarchan, Shakespearean, or Spenserian, among others. Many sonnets are part of a sonnet sequence, or series of sonnets on the same theme.

Iambic pentameter is a rhythm of five feet per line. Each foot has one unstressed syllable followed by a stressed syllable, making a total of ten syllables per line. Although the basic structure of a sonnet is always iambic pentameter, most poets vary the meter slightly to add interest and emphasize certain words.

The volta, or turn, is the conclusion of the poem. Sonnets draw the reader in at the beginning with a question, problem, or a simple observation to consider. A volta can answer the question, solve the problem, or present a new idea. At times, the volta in a sonnet is signaled with a dash or the word “yet.”

Petrarchan sonnets, sometimes called Italian sonnets, are modeled after the sonnets of Francesco Petrarca, a fourteenth century Italian humanist. This type of sonnet consists of an octave and a sestet, typically with a rhyme scheme of ABBAABBA CDECDE. Generally the volta in a Petrarchan sonnet occurs in the first line of the sestet, when the rhyme changes.

Shakespearean sonnets are named for late sixteenth century English poet and playwright William Shakespeare. Also known as Elizabethan sonnets, they are composed of three quatrains and a couplet, traditionally with a rhyme scheme of ABAB CDCD EFEF GG. A quatrain contains four lines of poetry, usually with alternating rhymes. A couplet, on the other hand, contains two lines of the same length that both end in words that rhyme. Although the volta can occur anywhere in a Shakespearean sonnet, it is typically at the beginning of the last couplet.

Some sonnets are neither Petrarchan nor Shakespearean. Sixteenth century poet Edmund Spenser wrote sonnets with a rhyme scheme of ABAB BCBC CDCD EE, now named the Spenserian sonnet in his honor. The structure of a sonnet can rely on other rhyme schemes or even on blank verse, such as in the poems of John Milton and Robert Lowell.

Placement in a sonnet sequence makes the structure of a sonnet larger than the sonnet itself. Any group of sonnets with one theme, such as Petrarch’s Il Canzoniere, is known as a sonnet sequence. A corona is a specific sonnet sequence in which the last line of one sonnet is the first line of the next, and the last line of the last poem is the first line of the first poem. Even more complicated is the sonnet redoublé, which contains fourteen sonnets in the form of a corona, and a fifteenth sonnet composed simply of the shared lines of the corona.