Opera is the Italian term of international use for a theatrical and musical genre in which the scenic action is combined with music, ballet and singing. The name “opera” is the conventional abbreviation of the noun phrase opera in musica.
Although other nations also have operatic traditions of undeniable importance and value, the genre was born and developed in Italy, a country that therefore has the largest number of opera houses in the world and is universally considered to be the birthplace of the opera.
The prose theater operates by means of stage designs and costumes and through acting. The specially composed literary text, which contains dialogues and captions, is called libretto. The singers are accompanied by an instrumental ensemble of varying sizes, including a large symphony orchestra. From its first appearance, the opera sparked passionate disputes between intellectuals, aimed at establishing whether the most important element was the music or the poetic text.
The subjects represented are various and may correspond to certain subgenres: serious, funny, playful, half-serious, farcical. The opera is conventionally divided into various “musical numbers”, which include both ensemble moments such as duets, terzettos, concertatos, choirs, ballets, and solos such as arias, ariosos, romances, cavatinas, cabalettas.
The staging (scenography, direction, costumes and eventual choreography) is therefore of fundamental importance, as well as the acting but, above all the vocal quality of the singers. If the resources for a stage production are insufficient, especially if the work requires a particularly elaborate staging, the opera can be performed in concert form.
Male voices are called, from the lowest to the highest, bass, baritone, tenor. To these main tones can be added the voices of countertenor (or contraltista) and sopranista, who use a falsetto setting in imitation of the female voice. They perform roles once entrusted to the castrati.
Female voices are classified, from the lowest to the highest, as contralto, mezzo-soprano and soprano. They perform, much more frequently than the corresponding male voices, the sopranista and/or contraltista roles written for the castrati.
Finally we have different types of opera, each with certain characteristics: Opera Seria, Opera Buffa,
Melodramma Giocoso, Opera Semiseria, Farsa, Singspiel, Opera-Comiquè, Gran Doperà, Music Drama.
Source: Wikipedia