In music, an intermezzo, in the most general sense, is a composition which fits between other musical or dramatic entities, such as acts of a play or movements of a larger musical work. In music history, the term has had several different usages, which fit into two general categories: the opera intermezzo and the instrumental intermezzo.

In the history of music this term has had different meanings. In particular the eighteenth-century operatic genre of the intermezzo can be distinguished, the symphonic intermezzo that separates the acts of the works and the instrumental interlude.

Renaissance intermezzo
The Renaissance intermezzo was also called the intermedio. 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. By the late 16th century, the intermezzo had become the most spectacular form of dramatic performance, and an important precursor to opera. The most famous examples were created for Medici weddings in 1539, 1565, and 1589. 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.

Opera intermezzo
The intermezzo, in the 18th century, was a comic operatic interlude inserted between acts or scenes of an opera seria. These intermezzi could be substantial and complete works themselves, though they were shorter than the opera seria which enclosed them; typically they provided comic relief and dramatic contrast to the tone of the bigger opera around them, and often they used one or more of the stock characters from the opera or from the commedia dell’arte. In this they were the reverse of the Renaissance intermezzo, which usually had a mythological or pastoral subject as a contrast to a main comic play. Often they were of a burlesque nature, and characterized by slapstick comedy, disguises, dialect, and ribaldry. The most famous of all intermezzi from the period is Pergolesi’s La serva padrona, which was an opera buffa that after the death of Pergolesi kicked off the Querelle des Bouffons.

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. In the 1730s the style spread around Europe, and some cities—for example Moscow—recorded visits and performances by troupes performing intermezzi years before any actual opera seria were done.

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).

The word was used (with a hint of irony) as the title of Richard Strauss’s two-act opera, Intermezzo (1924), the scale of which far exceeds the intermezzo of tradition.

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.

Instrumental intermezzo
In the 19th century, the intermezzo acquired another meaning: an instrumental piece which was either a movement between two others in a larger work, or a character piece which could stand on its own. These intermezzi show a wide variation in the style and function: in Mendelssohn’s incidental music to A Midsummer Night’s Dream the intermezzo serves as musical connecting material for action in Shakespeare’s play; in chamber music by Mendelssohn and Brahms, the intermezzi are names for interior movements which would otherwise be called scherzi; and the piano intermezzi by Brahms, some of his last compositions, are sets of independent character pieces not intended to connect anything else together. Stylistically, intermezzi of the 19th century are usually lyrical and melodic, especially compared to the movements on either side, when they occur in larger works. 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.

Opera composers sometimes wrote instrumental intermezzi as connecting pieces between acts of operas. In this sense, an intermezzo is similar to the entr’acte. The most famous of this type of intermezzo is probably the intermezzo from Mascagni’s Cavalleria rusticana. Puccini also wrote intermezzi for Manon Lescaut and Madama Butterfly, and examples exist by Wolf-Ferrari, Delius and others.

Also, incidental music for plays usually contained several intermezzi. Schubert’s Rosamunde music as well as Grieg’s Peer Gynt contained several intermezzi for the respective plays.

In the 20th century, the term was used occasionally. Shostakovich named one movement of his dark String Quartet No. 15 “intermezzo”; Bartók used the term for the fourth movement (of five) of his Concerto for Orchestra.

Symphonic Intermezzo and Entr’acte
The operatic form of the intermezzo, typical of the melodrama of the second half of the nineteenth and twentieth centuries, derives from the analogous French form of the entr’acte, of which it contains the descriptive character. It is sometimes combined with a program, described in the booklet. It is in fact a prelude which, instead of preceding the first act, is placed immediately before one of the successive acts or even during an act. Normally the symphonic interludes are thought to be performed with the curtain closed, but with some exceptions.

Examples of symphonic interludes
Lohengrin by Richard Wagner (1850 – Act III)
Carmen by Georges Bizet (1875 – acts II, III, IV – entr’acte )
The Prodigal Son of Amilcare Ponchielli (1880 – Act IV)
Le Villi by Giacomo Puccini (1884 – act II: in two parts entitled “L’abbandono” and “La tregenda”)
Marion Delorme of Amilcare Ponchielli (1885 – act IV)
Edgar by Giacomo Puccini (1889 – acts III and IV)
Cavalleria rusticana by Pietro Mascagni (1890 – during the single act)
The friend Fritz by Pietro Mascagni (1891 – act III)
Pagliacci by Ruggero Leoncavallo (1892 – Act II)
I Rantzau by Pietro Mascagni (1892 – act IV)
Werther by Jules Massenet (1892 – act IV)
Hänsel und Gretel by Engelbert Humperdinck (1893 – Act III)
Manon Lescaut by Giacomo Puccini (1893 – Act III)
Thaïs by Jules Massenet (1894 – Act II – known as Meditation )
Guglielmo Ratcliff by Pietro Mascagni (1895 – acts III and IV)
Adriana Lecouvreur by Francesco Cilea (1902 – act IV)
Madama Butterfly by Giacomo Puccini (1904 – Act III – originally a curtain opened in mid-act II)
Suor Angelica by Giacomo Puccini (1918 – before the finale, with the curtain open)
Billy Budd by Benjamin Britten (1951 – between the second and third framework of Act III)

Source from Wikipedia