Poetry can be analyzed in terms of a variety of structural features ranging from sound patterns to the visual appearance of the poem. Of these features, rhyme scheme, or the pattern of repeating sounds at the ends of lines, and stanza structure, the arrangement and grouping of related lines, offer key ways to characterize and categorize poetic works.
Rhythm and Rhyme
Rhythm and rhyme are key features of poetry. Although all poems have rhythm, or repetitions in patterns of stressed and unstressed syllables, not all poems rhyme. Rhyme refers to repeating patterns of identical sounds at word end, such as June and moon, or pardon and garden. Although rhyme is most recognizable at the end of a line of poetry, it can also occur inside a line, as internal rhyme. Some forms of poetry, such as free verse or prose poetry, are rich in rhythm but do not have rhyme.
Rhyme Scheme Patterns
A poem's rhyme scheme is the pattern of repeating rhymed syllables at the end of its lines. To establish a poem's dominant rhyme scheme, each line is assigned a different letter of the alphabet until a matching rhyme appears. That line is given the same letter as the line with which it rhymes, and this pattern is repeated until all rhyming lines are identified. For example, the first stanza of Edwin Arlington Robinson's poem "Richard Cory" has an ABAB rhyme scheme: "Whenever Richard Cory went downtown (A) /We people on the pavement looked at him(B) /He was a gentleman from sole to crown (A; rhymes with "town") /Clean-favored and imperially slim (B; rhymes with "him")."
A stanza is a group of lines related by rhythm, meter or other structural features. Usually delineated by spacing, stanzas may also be connected thematically or semantically, and vary in length from two to several lines, sometimes within the same poem. Some poems consist of only one stanza, while others, especially long poems, have many stanzas. William Carlos Willams' poem titled "The Red Wheelbarrow, although only six lines long, has three stanzas:" "(stanza 1) so much depends/upon/ (stanza 2) a red wheel/barrow/ (stanza 3) glazed with rain/water." Unrhymed poetry can also have stanzas, even though rhyme is not a factor.
Stanza and Rhyme Scheme
In rhyming poetry, rhyme plays a role in defining stanza structure, and rhyme schemes can span more than one stanza to unify the poem. Stanzas can share a single rhyme scheme, or they may be part of a larger pattern, as in Robert Frost's poem "Acquainted With the Night,: which has an ABAB pattern that extends across the first stanza and into the second: "I have been one acquainted with the night. (A) /I have walked out in rain -- and back in rain. (B) /I have outwalked the furthest city light.(A) / (Stanza 2) I have looked down the saddest city lane (B) ..."