A concerto (/kənˈtʃɛərtoʊ/; plural concertos, or concerti from the Italian plural) is, from the late Baroque era, mostly understood as an instrumental composition, written for one or more soloists accompanied by an orchestra or other ensemble. The typical three-movement structure, a slow movement (e.g., lento or adagio) preceded and followed by fast movements (e.g., presto or allegro), became a standard from the early 18th century.
The concerto originated as a genre of vocal music in the late 16th century: the instrumental variant appeared around a century later, when Italians such as Giuseppe Torelli and Arcangelo Corelli started to publish their concertos. A few decades later, Venetian composers, such as Antonio Vivaldi, had written hundreds of violin concertos, while also producing solo concertos for other instruments such as a cello or a woodwind instrument, and concerti grossi for a group of soloists. The first keyboard concertos, such as George Frideric Handel's organ concertos and Johann Sebastian Bach's harpsichord concertos, were written around the same time.