What Is a Rhyme Scheme? The Pattern That Tells You When a Thought Ends

A rhyme scheme is written by assigning a letter to each rhyme sound in order of appearance, so the first line is A, any later line rhyming with it is also A, the next new sound is B, and so on. A four-line stanza rhyming the second and fourth lines is ABCB, one rhyming alternate lines is ABAB, one rhyming in pairs is AABB, and one where the outer lines rhyme around an inner pair is ABBA. That last arrangement, the enclosed or envelope rhyme, has a quite different feel from the alternating version because the ear waits across two lines before the pattern closes, which slows the stanza and produces a sense of enclosure that poets have used deliberately, most famously in a Victorian elegy written entirely in it. Unrhymed lines are conventionally marked X. Additional notation handles refrains, repeated whole lines, and half rhyme, where sounds correspond partially rather than exactly. The system is a description rather than a rule, and its value is that it makes comparison across poems and traditions possible at a glance.

Several patterns became standardised forms carrying their own conventions of length, subject and turn:

• •The Italian sonnet, an eight-line section rhyming ABBAABBA followed by a six-line section, with a turn in argument at the join
• •The English sonnet, three alternating quatrains and a closing couplet, which shifts the weight of the turn to the final two lines and makes them epigrammatic
• •Terza rima, a chain of ABA BCB CDC in which the middle rhyme of each stanza seeds the next, producing forward momentum and no natural stopping point, used for the Divine Comedy
• •The ballad stanza, ABCB in alternating four and three stress lines, which is the form of most traditional song and of a great deal of hymnody
• •The villanelle, with two refrains recurring in a fixed pattern across nineteen lines, whose obsessive return suits poems of grief and insistence
• •The ghazal, an Arabic and Persian form of couplets sharing a rhyme and a repeated word, in which each couplet stands alone thematically

A scheme creates expectation, and expectation is the raw material of effect. Once a listener has heard two rhymed lines they anticipate the third, and the poet controls when that anticipation is satisfied, delayed or refused. A closing couplet after alternating rhyme snaps shut, which is why it suits summary, reversal and the sting in the tail. A long delay between a rhyme and its partner holds a thought open. A rhyme arriving on an unexpected word makes that word prominent, so schemes are a way of directing emphasis without any change in wording. Deliberate failure is equally usable: a poem that establishes a pattern and then breaks it at a specific moment marks that moment forcefully, and the break is only available because the pattern was there. Rhyme also aids memory substantially, which is why oral traditions, proverbs, advertising and children's verse rhyme, and there is evidence that rhyming statements are judged more truthful than equivalent non-rhyming ones, an effect studied under the name of the rhyme as reason bias.

How easily a language rhymes shapes what its poetry does. Italian and Spanish have many words ending in the same small set of vowel sounds and a limited range of endings, which makes rhyme easy and therefore cheap, so their traditions demand elaborate schemes to make it interesting. English has a large vocabulary drawn from several sources with varied endings, which makes rhyme comparatively hard, and the difficulty is part of why blank verse without rhyme became the standard for serious English drama and long poems. French rhymes on a different principle involving the gender of the ending. Classical Latin and Greek poetry did not rhyme at all and organised verse by syllable length instead. Chinese classical poetry rhymes but also patterns tones. Arabic monorhyme sustains a single rhyme across an entire long poem, which would be nearly impossible in English. Rap and hip hop substantially expanded English rhyming practice by using multisyllabic and internal rhyme densely, which is a genuine technical development rather than a loosening of standards.

Letters assigned to each new sound describe the pattern, and the arrangement changes the feel, with enclosed rhyme slowing a stanza and a closing couplet snapping it shut. Schemes create expectation, so a poet controls emphasis by when the partner arrives and marks a moment by breaking the pattern. Languages rhyme with different ease, which is why Italian demands elaborate schemes and English drama largely abandoned rhyme.