Swing music is a form of jazz that developed in the United States in the 1930s and 1940s. The name came from the emphasis on the off–beat, or weaker pulse. Swing bands usually featured soloists who would improvise on the melody over the arrangement. The danceable swing style of big bands and bandleaders such as Benny Goodman was the dominant form of American popular music from 1935 to 1946, known as the swing era. The verb "to swing" is also used as a term of praise for playing that has a strong groove or drive.
Swing has its roots in 1920s dance music ensembles, which began using new styles of written arrangements, incorporating rhythmic innovations pioneered by Louis Armstrong and Earl Hines. After World War II Swing began to decline in popularity, and jump blues and bebop gained popularity.