A chorus or, in Spanish, estribillo, is a term that is not to be confused with the Chorus that appears in Greek drama. This chorus refers to a refrain or a repeated phrase or line that is used again and again throughout a poem or a song. Often this is used to highlight or reinforce that line, which can relate to the key theme of that poem. For example, in "Tichbourne's Elegy" by Charles Tichbourne, the repeated refrain or chorus is "and now my life is done." Every stanza ends in this way, and this refrain is shown to emphasise his feelings of profound regret and his fear of the doom that awaits him at his execution.
Another famous example might be "Do not go gentle into that good night" by Dylan Thomas, where the famous chorus is repeated throughout the poem and ends the poem in the final stanza:
Do not go gentle into that good night.
Rage, rage against the dying of the light.
This refrain is used to give the poem tragic intensity as the son urges his father to not simply give in to death but to "rage against the dying of the light." Partly, the refrain in this poem is because of the structure, as this poem is a villanelle, which is a particular poem with a very precise structure. But at the same time, the refrain keeps the focus of this poem on the central theme which is about how humans meet death.
In the poem "The House that Jack Built," is a key example of chorus. "Bringing the Rain to Kapiti Plain," "Why Mosquitoes Buzz in People's Ears," "I Know an old Lady who Swallowed a Fly," and "The Very Hungry Caterpillar" are also good examples. Any other literature where a line or theme is repeated on a regular basis, like the chorus of a song, is an example.