Poets can use any structure they want when creating. The poem simply needs a particular arrangement of words on the page for heightened emotional effect. However, various cultures have created poetic structures intended to create specific emotions, arranged in standardized ways. The structures of many of the common poetic forms govern the length of the lines and where the poems rhyme.
Poetry analysts use letters of the alphabet to show which lines rhyme. So, if a poem is abab, the first and third lines rhyme, as do the second and fourth. The sonnet is a poem with 14 lines. Sonnets use one of several set rhyme schemes. The two main sonnet types are the Italian and English version. The Italian sonnet has one division of eight rhyming lines, in "abbabba." The second division has six rhyming lines, which are either "cdecde, "cdccdc," or "cdedce." The English sonnet has four divisions, called quatrains. The sonnet proceeds as "abab," "cdcd," "efef" and "gg."
The sestina was invented by French troubadours, a type of entertainer. Sestina was developed as the troubadours competed to create the best poems. The poem has six stanzas of blank verse that all have six lines. The last couple of words in the first stanza appear throughout the remaining five stanzas. The poem has "abcdef," "faebdc," "cfdabe," "ecbfad," "deacfb" and "bdfeca."
The villanelle is another French poem. Before it became a literary form, it was usually an old Italian folk song performed with a dance. It only has two rhymes and an alternating refrain. The poem has five tercets and a final quatrain. The villanelle usually has a three-part structure, which is the introduction, development and conclusion. The content of the villanelle usually focuses on some type of obsession.
The haiku is a Japanese form of poetry designed to be very compact. Haiku poems can focus on everyday experiences, feelings and nature. Because haikus have limited space, they must use simple words and grammar. Haikus do not rhyme and are short. The most common only have three lines, with the middle line having seven syllables and the first and last lines five. This brevity can sometimes make the poem harder to write, because it must create a memorable image with few words.
Odes are long and serious poems that use elaborate structure. The original odes were Greek and Roman. Odes usually gave praise to a person, such as someone who succeeds during an athletic event. Odes usually have structure, but the poet can choose the structure, which gives this poem an often irregular form.
Limericks are poems with five lines. One line is a couplet and one is a triplet. Lines 1, 2 and 5 have an aabba pattern. Lines 3 and 4 have two beats that rhyme. Limericks are written to be funny. The last line of the limerick is meant to deliver a punch line.