Aria in the context of "BWV 1"

Opera is a form of Western theatre in which music is a fundamental component and dramatic roles are taken by singers. Such a "work" (the literal translation of the Italian word "opera") is typically a collaboration between a composer and a librettist and incorporates a number of the performing arts, such as acting, scenery, costume, and sometimes dance or ballet. The performance is typically given in an opera house, accompanied by an orchestra or smaller musical ensemble, which since the early 19th century has been led by a conductor. Although musical theatre is closely related to opera, the two are considered to be distinct from one another.

Opera is a key part of Western classical music, and Italian tradition in particular. Originally understood as an entirely sung piece, in contrast to a play with songs, opera has come to include numerous genres, including some that include spoken dialogue such as Singspiel and Opéra comique. In traditional number opera, singers employ two styles of singing: recitative, a speech-inflected style, and self-contained arias. The 19th century saw the rise of the continuous music drama.

Singing is the art of creating music with the voice. It is the oldest form of musical expression, and the human voice can be considered the first musical instrument by some. The definition of singing varies across sources. Some sources define singing as the act of creating musical sounds with the voice. Other common definitions include "the utterance of words or sounds in tuneful succession" or "the production of musical tones by means of the human voice".

A person whose profession (or hobby) is singing is called a singer or a vocalist (in jazz or popular music). Singers perform music (arias, recitatives, songs, etc.) that can be sung with or without accompaniment by musical instruments. Singing is often done in an ensemble of musicians, such as a choir. Singers may perform as soloists or accompanied by anything from a single instrument (as in art songs or some jazz styles) up to a symphony orchestra or big band. Many styles of singing exist throughout the world.

Wilhelm Richard Wagner (/ˈvɑːɡnər/ VAHG-nər; German: [ˈvɪlˌhɛlm ˈʁɪçaʁt ˈvaːɡnɐ] ; 22 May 1813 – 13 February 1883) was a German composer, theatre director, essayist, and conductor, best known for his operas—although his mature works are often referred to as music dramas. Unlike most composers, Wagner wrote both the libretti and the music for all of his stage works. He first achieved recognition with works in the Romantic tradition of Carl Maria von Weber and Giacomo Meyerbeer, but revolutionised the genre through his concept of the Gesamtkunstwerk ("total work of art"), which sought to unite poetic, musical, visual, and dramatic elements. In this approach, the drama unfolds as a continuously sung narrative, with the music evolving organically from the text rather than alternating between arias and recitatives. Wagner outlined these ideas in a series of essays published between 1849 and 1852, most fully realising them in the first half of his four-opera cycle Der Ring des Nibelungen (The Ring of the Nibelung).

Wagner's compositions, particularly in his later period, have complex textures, rich harmonies and orchestration, and elaborate leitmotifs—musical phrases associated with individual characters, places, ideas, or plot elements. His advances in musical language, such as extreme chromaticism and quickly shifting tonal centres, greatly influenced the development of classical music; his Tristan und Isolde is regarded as an important precursor to modernist music. Later in life, he softened his ideological stance against traditional operatic forms (e.g., arias, ensembles and choruses), reintroducing them into his last few stage works, including Die Meistersinger von Nürnberg (The Mastersingers of Nuremberg) and Parsifal.

A sung-through or through-sung work is a narrative work such as a stage musical, musical film or opera in which the entire libretto is set to music, with little or no spoken dialogue or monologues used to tell the story. The story is told through a combination of aria, arioso and recitative. Early versions of this include the Italian genre of opera buffa, a light-hearted form of opera that gained prominence in the 1750s. Since Jesus Christ Superstar, sung-through musicals have been increasingly popular, with one commentator writing, "Hamilton demonstrates ... that a sung-through musical can be as vigorous in its storytelling as any more traditional book musical."

A Singspiel (German pronunciation: [ˈzɪŋʃpiːl] ; plural: Singspiele; lit. 'sing-play') is a form of German-language music drama, now regarded as a genre of opera. It is characterized by spoken dialogue, which is alternated with ensembles, songs, ballads, and arias which were often strophic, or folk-like. Singspiel plots are generally comic or romantic in nature, and frequently include elements of magic, fantastical creatures, and comically exaggerated characterizations of good and evil.

Opéra comique (French: [ɔpeʁa kɔmik]; plural: opéras comiques) is a genre of French opera that contains spoken dialogue and arias. It emerged from the popular opéras comiques en vaudevilles of the Fair Theatres of St Germain and St Laurent (and to a lesser extent the Comédie-Italienne), which combined existing popular tunes with spoken sections. Associated with the Paris theatre of the same name, opéra comique is not necessarily comical or shallow; Carmen, perhaps the most famous opéra comique, is a tragedy.

A number opera (Italian: opera a numeri; German: Nummeroper; French: opéra à numéros) is an opera consisting of individual pieces of music ('numbers') which can be easily extracted from the larger work. They may be numbered consecutively in the score, and may be interspersed with recitative or spoken dialogue. Opera numbers may be arias, but also ensemble pieces, such as duets, trios, quartets, quintets, sextets or choruses. They may also be ballets and instrumental pieces, such as marches, sinfonias, or intermezzi. The number opera format was standard until the mid-19th century and most opera genres, including opera seria, opera buffa, opéra comique, ballad opera, Singspiel, and grand opera, were constructed in this fashion.

The replacement of numbers with more continuous music began in operas by Jommelli, Traetta, Gluck, and especially Mozart, whose late operas Le Nozze di Figaro and Don Giovanni contain several segments in which different numbers are unified by bridge passages to form a musical whole. This trend became even more striking in the operas of the German composers Beethoven, Weber, and Meyerbeer, while their Italian and French contemporaries Rossini, Donizetti, Bellini, and Auber retained the number opera style.

Recitative (/ˌrɛsɪtəˈtiːv/, also known by its Italian name recitativo ([retʃitaˈtiːvo]) is a style of delivery (much used in operas, oratorios, and cantatas) in which a singer is allowed to adopt the rhythms and delivery of ordinary speech. Recitative does not repeat lines as formally composed songs do. It resembles sung ordinary speech more than a formal musical composition.

Recitative can be distinguished on a continuum from more speech-like to more musically sung, with more sustained melodic lines. The mostly syllabic recitativo secco ("dry", accompanied only by continuo, typically cello and harpsichord) is at one end of the spectrum, through recitativo accompagnato (using orchestra), the more melismatic arioso, and finally the full-blown aria or ensemble, where the pulse is entirely governed by the music. Secco recitatives can be more improvisatory and free for the singer, since the accompaniment is so sparse; in contrast, when recitative is accompanied by orchestra, the singer must perform in a more structured way.