It was a masque-like dramatic piece with music, which was performed between the acts of a play at Italian court festivities on special occasions, especially weddings.
In Baroque Spain the equivalent entremés or paso was a one-act comic scene, often ending in music and dance, between jornadas (acts) of a play.
In some cases the intermezzo repertory spread more quickly than did the opera seria itself; the singers were often renowned, the comic effects were popular, and intermezzi were relatively easy to produce and stage.
The intermède (the French equivalent of the intermezzo) was the single most important outside operatic influence in Paris in the mid-18th century, and helped create an entire new repertory of opera in France (see opéra comique).
Many of the most celebrated intermezzi are from operas of the verismo period: Mascagni's Cavalleria rusticana and L'amico Fritz, Leoncavallo's Pagliacci, Puccini's Manon Lescaut and Suor Angelica, Giordano's Fedora, Cilea's Adriana Lecouvreur, and especially that from Massenet's Thais, which became known as the Méditation.
The Brahms piano intermezzi in particular have an extremely wide emotional range, and are often considered some of the finest character pieces written in the 19th century.