Swing music, also known as swing jazz or simply swing, is a form of jazz music that developed in the early 1930s and became a distinctive style by 1935 in the United States. Swing uses a strong rhythm section of double bass and drums as the anchor for a lead section of brass instruments such as trumpets and trombones, woodwinds including saxophones and clarinets, and sometimes stringed instruments such as violin and guitar, medium to fast tempos, and a “lilting” swing time rhythm. Swing bands usually featured soloists who would improvise on the melody over the arrangement. The danceable swing style of bandleaders such as Benny Goodman and Count Basie was the dominant form of American popular music from 1935 to 1945.
The verb “to swing” is also used as a term of praise for playing that has a strong rhythmic “groove” or drive.
(extract from Wikipedia )