Swing music, or simply Swing, is a form of American music that developed in the early 1930s and became a distinctive style by 1940. 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. The name swing came from the phrase ‘swing feel’ where the emphasis is on the off–beat or weaker pulse in the music (unlike classical music). Swing bands usually featured soloists who would improvise on the melody over the arrangement. The verb "to swing" is also used as a term of praise for playing that has a strong rhythmic "groove" or drive.