A French Form
This is a poem of five stanzas of tercets (units of three lines) and a final one of a quatrain (four lines). There is no fixed metre, though iambic pentameters are often used in English. Lines one and three are repeated alternately as the last line of succeeding tercets, and as a final rhymed couplet. Showing the repeated lines as capitals, the rhyme scheme used is therefore AbÂ abA abÂ abA abÂ abAÂ. For a more detailed discussion of this popular form, see What is a Villanelle? on the More Words section.
A tutorial on the writing of villanelles by Jim Bartlett, plus an example poem written in response to it by Cat Ginn, can be seen by opening this PDF file: