An impromptu (, , loosely meaning "offhand") is a free-form musical composition with the character of an ex tempore improvisation as if prompted by the spirit of the moment, usually for a solo instrument, such as piano. According to Allgemeine musikalische Zeitung, Johann Baptist Cramer began publishing piano pieces under the (sub-)title of "impromptu." (AMZ, Mar. No II, 1815, col. 6), which seems to be the first recorded use of the term impromptu in this sense.
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