Quatrain
A four-line stanza in a poem, the first four lines and the second four lines in a Petrachan sonnet. A Shakespearean sonnet contains three of them followed by a couplet.

Couplet
A pair of rhymed lines that may or may not constitute a separate stanza in a poem. Shakespeare’s sonnets end in rhymed ones, as in “For thy sweet love remembered such wealth brings / That then I scorn to change my state with kings.”

Octave
An eight-line unit, which may constitute a stanza; or a section of a poem, as in one of a sonnet.

Sestet
A six-line unit of verse constituting a stanza or section of a poem; the last six lines of an Italian sonnet. Examples: Petrarch’s “If it is not love, then what is it that I feel,” and Frost’s “Design.”

Ballad
A narrative poem written in four-line stanzas, characterized by swift action and narrated in a direct style. The Anonymous medieval one, “Barbara Allan,” exemplifies the genre.

Parody
A humorous, mocking imitation of a literary work, sometimes sarcastic, but often playful and even respectful in its playful imitation. Examples include Bob McKenty’s one of Frost’s “Dust of Snow” and Kenneth Koch’s one of Williams’s “This is Just to Say.”

Elegy
A lyric poem that laments the dead. Robert Hayden’s “Those Winter Sundays” is like this in tone. A more explicitly identified one is W.H. Auden’s “In Memory of William Butler Yeats” and his “Funeral Blues.”

Blank verse
A line of poetry or prose in unrhymed iambic pentameter. Shakespeare’s sonnets, Milton’s epic poem Paradise Lost, and Robert Frost’s meditative poems such as “Birches” include many lines of one. Here are the opening lines of “Birches”: When I see birches bend to left and right / Across the lines of straighter darker trees, / I like to think some boy’s been swinging them.

Narrative poem
A poem that tells a story.

Epic
A long narrative poem that records the adventures of a hero. They typically chronicle the origins of a civilization and embody its central values. Examples from western literature include Homer’s Iliad and Odyssey, Virgil’s Aeneid, and Milton’s Paradise Lost.

Ode
A long, stately poem in stanzas of varied length, meter, and form. Usually a serious poem on an exalted subject, such as Horace’s “Eheu fugaces,” but sometimes a more lighthearted work, such as Neruda’s “___ to My Socks.”

Aubade
A love lyric in which the speaker complains about the arrival of the dawn, when he must part from his lover. John Donne’s “The Sun Rising” exemplifies this poetic genre.

Sestina
A poem of thirty-nine lines and written in iambic pentameter. Its six-line stanza repeat in an intricate and prescribed order the final word in each of the first six lines. After the sixth stanza, there is a three-line envoi, which uses the six repeating words, two per line.

Sonnet
A fourteen-line poem in iambic pentameter. The Shakespearean or English one is arranged as three quatrains and a final couplet, rhyming abab cdcd efef gg. The Petrarchan or Italian one divides into two parts: an eight-line octave and a six-line sestet, rhyming abba abba cde cde or abba abba cd cd cd.

Haiku
It’s a 17-syllable verse form consisting of three metrical units of 5, 7, and 5 syllables. Japanese poetry.

Villanelle
A nineteen-line lyric poem that relies heavily on repetition. The first and third lines alternate throughout the poem, which is structured in six stanzas –five tercets and a concluding quatrain. Examples include Bishop’s “One Art,” Roethke’s “The Waking,” and Thomas’s “Do Not Go Gentle into That Good Night.”

Closed form
A type of form or structure in poetry characterized by regularity and consistency in such elements as rhyme, line length, and metrical pattern. Frost’s “Stopping By Woods on a Snowy Evening” provides one of many examples. A single stanza illustrates some of the features of it

Whose woods these are I think I know.
His house is in the village though.
He will not see me stopping here
To watch his woods fill up with snow.

Open form
A type of structure or form in poetry characterized by freedom from regularity and consistency in such elements as rhyme, line length, metrical pattern, and overall poetic structure. E.E. Cummings’s “[Buffalo Bill’s]” is one example.

Free verse
Poetry without a regular pattern of meter or rhyme. The verse is “free” in not being bound by earlier poetic conventions requiring poems to adhere to an explicit and identifiable meter and rhyme scheme in a form such as the sonnet or ballad. Modern and contemporary poets of the twentieth and twenty-first centuries often employ this. Williams’s “This Is Just to Say” is one of many examples.