A big band or jazz orchestra is a type of musical ensemble of jazz music that usually consists of ten or more musicians with four sections: saxophones, trumpets, trombones, and a rhythm section. Big bands originated during the early 1910s and dominated jazz in the early 1940s when swing was most popular. The term “big band” is also used to describe a genre of music, although this was not the only style of music played by big bands.
Big bands started as accompaniment for dancing. In contrast to the typical jazz emphasis on improvisation, big bands relied on written compositions and arrangements. They gave a greater role to bandleaders, arrangers, and sections of instruments rather than soloists.