Form is the structure of a poem, including its line lengths, line breaks, meter, stanza lengths, and rhyme scheme. 

Every poem has a form, but some forms are unique to individual poems and some are more widely used and include their own set of rules and parameters. Specific poetic forms include sonnet, villanelle, haiku, and prose poem. Form refers to the appearance and sound of the poem, but it can also influence the tone or purpose of the poem. For example, many sonnets are love poems, so the tone of a poem written in the sonnet form might be reverent or yearning. 

Even though some forms observe specific rules, poets often break those rules to subvert readers’ expectations. For example, in “A Modified Villanelle for My Childhood,” Suzi F. Garcia changes the traditional villanelle form by adding three stanzas. In the final stanza, the speaker says “Did you know a poem can be both mythical and archeological? / I ignore the cataphysical, and I anoint my own clavicle,” asserting her own agency and control of the poem and the form. The deviation from the form becomes an essential aspect of the poem.

Examples of poems that use a variety of different forms include “Bright Star” by John Keats, “A Spray of Water: Tanka [the round spoon]” by Tada Chimako, “Hummingbird Abecedarian” by Aimee Nezhukumatathil, “It Is Maybe Time to Admit That Michael Jordan Definitely Pushed Off” by Hanif Abdurraqib, and “A Skull” by Dana Levin.