What Is a Sonnet? Form, Rhyme, and the Turn in a Poem

The most reliable feature of a traditional sonnet is its 14 lines. Beyond that, the exact rhyme scheme, meter, and organisation depend on the sonnet tradition being used. English sonnets often use iambic pentameter, but recognising a sonnet involves more than counting beats or looking for one rhyme pattern.

A useful answer to what a sonnet is should include structure and thought. Sonnets are compact, so poets often organise them around contrast. One part may introduce a question, describe a situation, or build an argument. A later part then answers, complicates, reverses, or reframes what came before. That change is often called the volta, meaning turn.

The English or Shakespearean sonnet commonly divides its 14 lines into three four-line quatrains followed by a two-line couplet. A familiar rhyme scheme is ABAB CDCD EFEF GG. The quatrains can develop an idea in stages, while the final couplet can summarise, challenge, twist, or sharpen the poem's argument.

When identifying a sonnet in this tradition, do not assume the final couplet always gives a simple answer. A poet can use it for surprise or ambiguity. The important point is that the structure creates expectations, and a skilled poet can either satisfy those expectations or deliberately resist them.

The Petrarchan or Italian sonnet traditionally separates into an octave of eight lines and a sestet of six lines. The octave often uses a rhyme pattern such as ABBAABBA, while the sestet is more variable. The volta commonly appears around the transition between these two larger parts.

This structure can make a change in thought especially noticeable. The octave might describe a conflict or desire, while the sestet responds from a new angle. When studying a sonnet, mark the rhyme pattern, identify groups of lines, and look for changes in argument or tone. Form matters most when you connect it to what the poem is doing rather than merely naming its parts.

Shakespeare's Sonnet 18, 'Shall I compare thee to a summer's day?', shows the machinery in action. The first quatrain proposes the comparison and starts finding faults with summer: too short, too windy. The second widens the complaint to everything in nature, which fades. The third turns, on the word 'But', to the beloved's eternal summer, which will not fade. The couplet explains why: as long as people read the poem, the beloved lives in it.

The volta lands at line nine, exactly where a Petrarchan sonnet would place it, even though the rhyme scheme is English. That is the kind of observation worth making in an essay, because it shows the poet using one tradition's turn inside another's structure, and it connects the form to the poem's argument about poetry outlasting time.

The sonnet began in Italy, where Petrarch made it famous in the fourteenth century with a long sequence of poems addressed to a woman he called Laura. It reached English in the early sixteenth century through Thomas Wyatt, who translated and imitated Petrarch, and Henry Howard, Earl of Surrey, who helped settle the pattern later used by Shakespeare. Rhyme is scarcer in English than in Italian, where many words share the same endings, so English poets moved towards schemes that needed fewer matching rhymes. That practical pressure is one reason the English form uses seven rhyme sounds instead of four or five.

Poets kept adapting the form. Edmund Spenser linked his quatrains with shared rhymes, ABAB BCBC CDCD EE, so the poem feels more tightly woven together. John Milton used the sonnet for politics and religion instead of love, and often let his sentences run over the break between octave and sestet. Gerard Manley Hopkins invented a shortened 'curtal' sonnet, and many twentieth century poets dropped regular rhyme altogether while keeping fourteen lines and a turn. When you meet an unusual sonnet, ask which expectation the poet has broken and what that break achieves.

Iambic pentameter means a line of five iambs, where each iamb is an unstressed syllable followed by a stressed one, giving a da-DUM pattern repeated five times. Reading the opening line of Sonnet 18 aloud shows it: shall I com-PARE thee TO a SUM-mer's DAY, with stresses falling on syllables such as pare, sum and day. A practical way to check a line is to count its syllables, which should usually be ten, then tap your hand on the stresses that come naturally when you speak.

Real poems rarely keep the pattern perfectly, and the variations are often where meaning lives. A line may open with a stressed syllable to give it extra force, or end with an extra unstressed syllable, called a feminine ending, which can make it sound softer or less resolved. Do not force words into an artificial rhythm to make them fit. Read the line as natural speech first, mark where the stresses actually fall, and then ask why the poet might have broken the regular beat at that particular moment.

By Shakespeare's time the sonnet came with a stock of familiar comparisons inherited from Petrarch and his many imitators. The beloved's eyes were suns, her lips coral, her cheeks roses, her breath perfume and her hair golden wire. Poets often praised the beloved's features one at a time, a technique called a blazon. These images had been repeated so often that they risked becoming clichés, and Shakespeare's Sonnet 130 exploits that. It begins 'My mistress' eyes are nothing like the sun' and goes on to deny each comparison in turn: coral is far redder than her lips, and her breath is no perfume.

The couplet then turns: 'And yet, by heaven, I think my love as rare / As any she belied with false compare.' The mockery was never aimed at the woman but at poets who praised with impossible exaggeration, and the volta reveals a love that does not need such flattery to be sincere. Sonnet 130 is a reminder that sonnets often respond to earlier sonnets. When you read one, ask whether its images are fresh or borrowed, and whether the poet is using the conventions straight, bending them gently, or openly arguing with them. That question can open up poems that seem simple at first.

John Milton's sonnet beginning 'When I consider how my light is spent', written after he lost his sight in the early 1650s, follows the Italian pattern closely. The octave rhymes ABBAABBA, on sounds such as spent, wide, hide and bent, and it sets out a problem. Milton fears that his 'one Talent', his gift for writing, now lies 'useless', echoing the parable in which a servant is punished for burying the money his master entrusted to him. The worry builds into a complaint against God: 'Doth God exact day-labour, light denied?'

The turn arrives early. Halfway through line eight, before the octave has finished, the speaker writes 'I fondly ask. But Patience, to prevent / That murmur, soon replies', and the sestet, rhyming CDECDE, belongs to that calmer voice. God, Patience explains, needs neither human work nor human gifts, and the poem ends on a famous line: 'They also serve who only stand and wait.' The early volta is worth pointing out in an essay, because the impatient complaint is cut off before it can complete its section of the form, so the structure acts out the poem's argument about accepting limits.

A sonnet is a 14-line poetic form with several traditions, including Shakespearean and Petrarchan structures. Look for rhyme, meter, groups of lines, and especially the volta. The strongest analysis explains how the poem's compact form helps develop or transform its central idea.