What is the defining characteristic of a villanelle?

A villanelle is a highly structured poetic form that is characterized by its specific arrangement of stanzas and a repeating rhyme scheme. The defining feature of a villanelle is that it consists of five tercets followed by a final quatrain. This means that there are five three-line stanzas and one four-line stanza. Additionally, the villanelle employs a fixed rhyme scheme of ABA throughout the tercets and the quatrain, where the first and third lines of the opening tercet are alternately repeated at the end of the following stanzas and both appear in the final quatrain. This unique structure lends a musical quality to the poem and emphasizes its themes through repetition, which is essential to the form. The choice that accurately describes this structure highlights the importance of form in poetry and helps to distinguish a villanelle from other types of poetic structures. Other options reference different forms or characteristics that do not apply to a villanelle.