Stanzas serve a range of functions in a poem. Some poets use stanzas in poetry to group ideas or images that belong together. Others indicate a change in tone, direction, or idea by creating a new stanza. Some poets play with the suggestion of silence that a stanza break implies, and still others use stanzas and the white spaces that divide them to create visual interest.
Many cultures have traditional poetic forms that impose a visual, imagistic, or audio "architecture" on a particular type of poem and force stanza breaks at predictable points. One example is the sonnet. Petrarchian, or Italian, sonnets are organized into two stanzas for a total of 14 lines; the first stanza is composed of eight lines, followed by a six-line stanza. English, or Shakespearean, sonnets are also 14 lines long but are organized in three quatrains, or four-line stanzas, followed by a couplet, or a two-line stanza.
Other traditional forms such as the haiku or villanelle organize themselves around tercets, or three-line stanzas in poetry. In the case of the haiku, originally a Japanese form that has gained a wide following among poets who write in English, a single tercet composes the entire poem. A villanelle, which has in roots in French troubadour tradition, contains several three-line stanzas that alternately repeat an entire line.
Poets writing in open form are not restricted in regard to where to place stanzas in poetry. These poets use stanza breaks for a multitude of intellectual, intuitive, or emotional reasons. To some, a stanza break gives the reader a chance to pause momentarily and reflect on the group of lines that have just completed. To others, a stanza break suggests surprise and often leads the poem in an entirely unexpected direction.
Visual poets, such as ee cummings and the later concrete poets, use the appearance of words, letters, numbers, and symbols on a page in a visually as well as linguistically artistic way. For these poets, stanzas in poetry are opportunities to create not just conceptually meaningful ideas or messages but visually charged ones as well. By creating unexpected patterns on the page, including stanza breaks that might present considerably more than two blank lines or stanzas that run horizontally rather than vertically, these poets not only present poems that cross media limits but poems that challenge reader anticipation and suggest that one of the functions of art is to shatter expectations.