Bebop or bop is a style of jazz developed in the early to mid-1940s in the United States. The style features compositions characterized by a fast tempo, complex chord progressions with rapid chord changes and numerous changes of key, instrumental virtuosity, and improvisation based on a combination of harmonic structure, the use of scales and occasional references to the melody.

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.