ses·ti·na 
(sĕ-stēnə)
(sĕ-stēnə)n.
A verse form first used by the Provençal troubadours, consisting of six six-line stanzas and a three-line envoy. The end words of the first stanza are repeated in varied order as end words in the other stanzas and also recur in the envoy.
[Italian, from sesto, sixth, from Latin sextus; see s(w)eks in the Appendix of Indo-European roots.]