The concerto and the concerto grosso (plural: concerti grossi) are the most important orchestral genres of the Baroque era. The basic idea underlying these genres is contrast between an orchestra and a soloist (in the concerto) or a small group of soloists (in the concerto grosso). Indeed, the word concerto comes from the Latin word concertare, to contend — an origin that accurately indicates a sort of contest between solo and orchestra. This contest pits the brilliance of the soloist or soloists against the relative power and stability of the orchestra. Contrast comes to these genres naturally.

Concertos and concerti grossi exemplify a large-scale approach to instrumental composition that was new in the Baroque era. Composers wanted large-scale forms because audiences, then as now, were more impressed by extended compositions than by short ones. They wanted them also because they could afford the opportunity to portray several different emotions or affects.