A triolet (/ˈtraɪ.əlᵻt/ or US /ˌtriː.əˈleɪ/) is a stanza poem of eight lines. Its rhyme scheme is ABaAabAB and often all lines are in iambic tetrameter: the first, fourth and seventh lines are identical, as are the second and final lines, thereby making the initial and final couplets identical as well.
The form stems from medieval French poetry - the earliest written examples are from the late 13th century. The triolet is a close cousin of the rondeau, another French verse form emphasizing repetition and rhyme. Some of the earliest known triolets composed in English were written by Patrick Cary, briefly a Benedictine at Douai, who purportedly used them in his devotions. British poet Robert Bridges reintroduced the triolet to the English language, where it enjoyed a brief popularity among late-nineteenth-century British poets.
An effective conventional triolet achieves two things; firstly the naturalness of the refrain and secondly the alteration of the refrain's meaning.