Country pianist Al Hopkins first used the term Hillbilly music in 1925 and was at one time considered an acceptable name for what is now known as Country & Western Music. This name was found offensive by some artists and fans, even in the height of its popularity, and by the 1950s was considered to be offensive and is now seldom used. Hillbilly music is now sometimes used to describe old-time music.
As early as the the 1920s, there were records by a band called the Beverly Hillbillies and the Delmore Brothers recorded the "Hillbilly Boogie" in 1946. Radio stations in the late forties used the term "hillbilly" to describe fiddlers and string bands, and the famous bluegrass fiddler Vassar Clements described his style of music as "hillbilly jazz." Eventually, the term became synonymous with the traditional music of the Appalachian Mountain region, even though the musicians that lived and performed in the Appalachian Mountains never used this term to describe their music.
In the late 1940s and early 1950s songs became popular that combined hillbilly and African American music and became known as hillbilly boogie, and later in the mid-1950s as rockabilly. The music of Elvis Presley's early career was arguably in the rockabilly genre. The music industry ultimately merged hillbilly music, Western Swing, and similar genres, to form the current category C&W, or Country & Western music.