Definition of "sestina"

Although the sestina is of medieval French origin, attributed to Arnaut Daniel in the late twelfth century and used by other Gallic poets and by Italians including Petrarch and Dante (from whom it received its Italian name), […]

2002, Annie Finch, Kathrine Varnes, An Exaltation of Forms: Contemporary Poets Celebrate the Diversity of Their Art, University of Michigan Press, page 290

Would he let others toil to support him while he languished all afternoon over his sestinas?

2022, Ian McEwan, Lessons, page 11