The Collaborative International Dictionary of English v.0.48:

Ballade \Bal*lade"\, n. [See Ballad, n.]
   A form of French versification, sometimes imitated in
   English, in which three or four rhymes recur through three
   stanzas of eight or ten lines each, the stanzas concluding
   with a refrain, and the whole poem with an envoy.
   [1913 Webster]

WordNet (r) 3.0 (2006):

ballade
    n 1: a poem consisting of 3 stanzas and an envoy