Opera (from the Italian òpera, musical works) designates a genre of theatrical music in which a stage action is harmonized, sung and has instrumental accompaniment. Performances are usually given in opera houses, accompanied by an orchestra or a smaller musical group. It is part of the European and Western classical music tradition.
Unlike the oratorio, the opera is a work meant to be performed. Some genres of musical theater are closely related to opera, such as the Spanish zarzuela, the German singspiel, the Viennese operetta, the French opéra-comique, and the English and American musical. Each of these variants of musical theater has its own characteristics, without these being exclusive to them and, on many occasions, giving rise to unclear borders between such genres. In opera, as in several other genres of musical theater, it joins:
- The music (orchestra, soloists, choir and director).
- Poetry (by means of the libretto).
- The performing arts, especially acting, ballet, and dance.
- The scenic arts (painting, plastic arts, decoration, architecture).
- Lighting and other scenic effects.
- Makeup and costumes.
Opera is usually differentiated from other musical theater genres by accepting that opera is a performance completely accompanied by music. The history of the genre shows that such a statement is not correct. Although opera differs from recited theater due to the extraordinary participation of music in its constitution, bordering forms such as the masquerade, the ballad opera, the zarzuela and the singspiel were already known from the Baroque period, which are confused in many cases with the opera. Thus, Wolfgang Amadeus Mozart’s singspiele are considered operas in the same way as José de Nebra’s zarzuelas, while Kurt Weill’s Die Dreigroschenoper (The Threepenny Opera) is, in reality, much closer to recited theater than to Opera. Finally, there are other genres close to opera, such as the French baroque opera-ballet and some 20th-century neoclassicist works, such as some works by Igor Stravinsky. However, in these works the main expressive part falls on the dance while the song is relegated to a secondary role. Regarding the difference between the opera and the zarzuela, the operetta, the singspiel and the English and American musical, the delimitation stems from a formal difference.