A ritornello is a musical term that refers to a recurring passage in a piece of music, particularly in the Baroque period. It typically serves as a refrain, contrasting with other sections or episodes of the music. The term is most commonly associated with the structure of concertos, especially in the works of composers like Antonio Vivaldi and Johann Sebastian Bach.
In a concerto, the ritornello is often played by the full orchestra and alternates with episodes played by the soloist(s) or smaller ensembles. This creates a dialogue between the ritornello and the contrasting sections, contributing to the overall form and thematic development of the piece. The ritornello is usually recognizable by its thematic material, which may return in varying keys or with different instrumentation throughout the work.