Ritornello

Ritornello is a short return or repetition; a concluding symphony to an air, often consisting of the burden of the song. Or a short intermediate symphony, or instrumental passage, in the course of a vocal piece; an interlude.

In Baroque music, Ritornello was the word for a recurring passage for orchestra in the first or final movement of a solo concerto. There was a passage for a solo instrument, usually the violin, between each ritornello. The most prolific Baroque composer in solo concertos was Antonio Vivaldi. When the classical music era started, the ritornello form was altered to resemble sonata form. The piano replaced the violin as the most frequently used solo instrument.