sestina

1. (poetry) A highly structured poem consisting of six six-line stanzas followed by a tercet or envoy, for a total of thirty-nine lines.Examples: "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), […]"; "Would he let others toil to support him while he languished all afternoon over his sestinas?"

2. (music) A chord comprising the first six members of the harmonic series.