A form of jazz music that developed during the 1920s and had solidified as a distinctive style by 1935 in the USA.

Swing is distinguished primarily by a strong rhythm section, usually including double bass and drums, medium to fast tempo, and the distinctive swing time rhythm that is common to many forms of jazz. Swing bands tended to be bigger and more crowded than other jazz bands, necessitating a slightly more detailed and organised type of composition and notation than was then the norm. Band leaders put more energy into developing arrangements, perhaps reducing the chaos that might result from as many as 12 or 16 musicians spontaneously improvising. But the best swing bands at the height of the era explored the full gamut of possibilities from spontaneous ensemble playing to highly orchestrated music in the vein of European art music.

A typical song played in swing style would feature a strong, anchoring rhythm section in support of more loosely tied wind, brass and, later, string and/or vocal sections. The level of improvisation that the audience might expect at any one time varied depending on the arrangement, the band, the song and the band-leader. The most common style consisted of having one soloist at a time taking centre stage and take up an improvised routine, with her/his bandmates playing support. As a song progressed, multiple soloists might be expected to pick up the baton and then pass it on. That said, it was common to have two or three band members improvising at any one time.

As swing jazz music began to grow in popularity throughout the USA, a number of changes occurred in the culture that surrounded the music. For one, the introduction of swing music, with its strong rhythms, loud tunes and style led to an explosion of creative dance in the black community. The various rowdy, energetic, creative, and improvisational dances that came into effect during that time came to be known, collectively, as swing dance. The second change that occurred as swing music increased in popularity outside the black community, was, to some extent, an increasing pressure on musicians and band leaders to soften or commercialise the music to cater to a more staid and conservative, Anglo-American audience.

Swing music began to decline in popularity during WWII, largely due to the difficulty of staffing and cost of maintaining and touring a big band during wartime. These factors made smaller 3 to 5 piece combos more profitable and manageable and led to the rise of jump blues and bebop. A further reason is the recording bans of 1942 and 1948 because of musicians' union strikes.