a 19th-century piano composition intended to produce the illusion of spontaneous improvisation. In keeping with this fundamental premise, there is no particular form associated with the impromptu, although ternary and rondo schemes are common. The style of the music is similar to that of other compositions of the period, with such designations as fantasie, caprice, and bagatelle.

The name impromptu first appeared in 1822 as the title of piano pieces by the Bohemian composer Jan Hugo Voříšek and the German Heinrich Marschner. Among the best-known impromptus are those by Franz Schubert (Opuses 90 and 142) and Frédéric Chopin (Opuses 29, 36, and 51). Impromptus were also written by Ludwig van Beethoven, Robert Schumann, Franz Liszt, Gabriel Fauré, and Aleksandr Scriabin.