Source : Webster's Revised Unabridged Dictionary (1913)

Ritornelle \Rit`or*nelle"\, Ritornello \Ri`tor*nel"lo\, n. [It.
   ritornello, dim. of ritorno return, fr. ritornare to return:
   cf. F. ritournelle.] (Mus.)
   (a) A short return or repetition; a concluding symphony to an
       air, often consisting of the burden of the song.
   (a) A short intermediate symphony, or instrumental passage,
       in the course of a vocal piece; an interlude.