"Rockabilly" usually (but not exclusively) refers to the type of rock and roll music which was played and recorded in the mid 1950s by white singers such as Elvis Presley, Carl Perkins and Jerry Lee Lewis, who drew mainly on the country roots of the music. Many other popular rock and roll singers of the time, such as Fats Domino and Little Richard, came out of the black rhythm and blues tradition, making the music attractive to white audiences, and are not usually classed as "rockabilly".
Rock and roll
Rock and roll (often written as rock & roll or rock ’n’ roll) is a genre of popular music that evolved in the United States after World War II in the late 1940s, from a combination of the rhythms of the blues, from the African American culture, and from America's country music and gospel music scenes. Though elements of rock and roll can be heard in country records of the 1930s, and in blues records from the 1920s, rock and roll did not acquire its name until the 1950s. An early form of rock and roll was rockabilly, which combined country and jazz, with influences from traditional Appalachian folk, and gospel music.