Rockabilly is one of the earliest styles of rock and roll music, dating to the early 1950s in the United States, especially the South. As a genre it blends the sound of Western musical styles such as country with that of rhythm and blues, leading to what is considered ""classic"" rock and roll. Some have also described it as a blend of the bluegrass style with rock and roll. The term ""rockabilly"" itself is a portmanteau of ""rock"" (from ""rock 'n' roll"") and ""hillbilly"", the latter a reference to the country music (often called ""hillbilly music"" in the 1940s and 1950s) that contributed strongly to the style. Other important influences on rockabilly include western swing, boogie woogie, jump blues and electric blues.Defining features of the rockabilly sound included strong rhythms, vocal twangs and common use of the tape echo, but the progressive addition of different instruments and vocal harmonies led to its ""dilution"". Initially popularized by artists such as Bill Haley, Elvis Presley, Carl Perkins, Johnny Cash, Bob Luman and Jerry Lee Lewis, the influence and success of the style waned in the 1960s; nonetheless, during the late 1970s and early 1980s, rockabilly enjoyed a major revival through acts such as Stray Cats. An interest in the genre endures even in the 21st century, often within a subculture. Rockabilly has left a legacy, spawning a variety of sub-styles and influencing other genres such as punk rock.