The Sonnet Form

Before we get too far into this guide, let’s make sure we’re all on the same page with some key words that’ll help us talk about the sonnets in more detail.

Poetry Words to Know

Stanza: A group of lines forming the basic recurring metrical unit of a poem. 

Quatrain: A quatrain is a four-line stanza. In Shakespeare’s sonnets, quatrains follow an ABAB rhyme scheme.

Tercet: A tercet is a three-line stanza. In Petrarch’s sonnets, tercets follow a CDE rhyme scheme.

Heroic couplet: A couplet is a pair of rhymed lines. A heroic couplet is a self-contained couplet of iambic pentameter (more on meter below).  

Octave: An eight-line verse form, usually consisting of two quatrains. In a sonnet, the octave establishes the theme, argument, and tone of the poem.

Sestet: A six-line verse form. In a sonnet, the sestet complicates the subject matter and themes of the poem before bringing it to a close.

Volta: The volta—best translated from Italian as “turn”—is a device found in all forms of literature. In a sonnet, the volta arrives between the octave and sestet, bringing about a notable shift in the poem. It signifies a change in the narrative, offering a contradiction or complication of the sonnet’s initial theme or argument. In Shakespeare’s sonnets, the volta manifests in a number of different ways. Words such as “but” and “then” at the beginning of a sonnet’s sestet announce the turn. It is also common for a volta to bring about both thematic and tonal shifts. At the volta, the speaker’s voice may turn from happy to sad, angry to resigned, brash to contemplative. 

Feminine Rhyme: A feminine rhyme is a rhyme between two words that have a stressed syllable followed by one or more unstressed syllables. For example, Sonnet 29 contains a feminine rhyme between the words “despising” and “arising.” Feminine rhymes are considered weak and subdued. The additional unstressed syllable lacks a sense of resolution. They can thematically underscore poems that focus on weakness, uncertainty, or anxiety as well.

Slant Rhyme: A slant rhyme is a rhyme between two words whose vowel sounds are similar, but not identical. One example is the slant rhyme between “come” and “doom” in Sonnet 116. In English poetry, slant rhymes are used for a variety of reasons. They open up more options in diction for the poet, and are often considered elegant in their subtlety. They can also cause the reader to pay closer attention to the poem as they offer an element of surprise or an unanticipated resolution. 

Conceit: A conceit is an extended metaphor that functions as a poem’s central metaphor. Conceits are often thought-provoking because they compare two unlike things. Not every poem employs a clear central conceit, but many of Shakespeare’s sonnets do. Sonnet 18 is built on a straightforward conceit. As the first line asks, “Shall I compare thee to a summer’s day?” The rest of the poem extends and explores this comparison between the Fair Youth and summer.

Sonnet Structure

The sonnet is a 14-line poem whose rhyme scheme and structure vary according to the specific style of sonnet. Each line in an English sonnet has 10-syllables and generally follows strict iambic pentameter (more on meter below). The classic Petrarchan sonnet, invented in Renaissance Italy, consists of four stanzas: two quatrains and two tercets. Its rhyme scheme is as follows: ABBA ABBA CDE CDE. In a Petrarchan sonnet, the volta—the thematic turn—is accentuated by the significant shift in the rhyme scheme.

The Shakespearean Sonnet 

The “Shakespearean Sonnet” is a misnomer because Shakespeare did not invent this form. In the 1540s, Sir Thomas Wyatt introduced the sonnet to England by imitating Petrarch’s sonnets in English verse. This form of the poem is called the “Shakespearean Sonnet” because his sequence became the most famous version of the English form. 

An English sonnet (or Shakespearean sonnet) differs in structure from the Petrarchan sonnet. Rather than using two quatrains and two tercets, Shakespeare’s sonnets use three quatrains and a couplet. Thus, the rhyme scheme of the Shakespearean sonnet is as follows: ABAB CDCD EFEF GG. 

In the English sonnet, the volta occurs at line 9 after the octave. In each of Shakespeare’s sonnets, pay attention to how Shakespeare controls the volta, the transition from the octave to the sestet. In some sonnets, the volta is clear and sudden. In others, it is subtle or nonexistent. There are even sonnets in which the volta arrives a line earlier or later than expected. Delayed or premature voltas can have thematic purpose. 

The final couplet represents another important shift in the poem. Because of the immediacy of its rhyme and its self-contained quality, the couplet is sudden and forceful. Shakespeare usually uses it to bolster the sonnet’s main point or offer a surprising twist to the main argument of the poem. 


The sonnets use iambic pentameter. This means each line consists of five iambs, or pairs of stressed and unstressed syllables. This form makes each line sonorous and lilting. The opening line of Sonnet 18 shows how this works, with the stressed syllables italicized:

Shall I com-pare thee to a sum-mer’s day?

Sometimes Shakespeare strays from iambic pentameter. When he does this, these metrical variations often marks a shift in the poem’s themes.