ルーツ・ミュージック
American traditional music is also called roots music. Roots music is a broad category of music including bluegrass, country music, gospel, old time music, jug bands, Appalachian folk, blues, Cajun and Native American music. The music is considered American either because it is native to the United States or because it developed there, out of foreign origins, to such a degree that it struck musicologists as something distinctly new. It is considered "roots music" because it served as the basis of music later developed in the United States, including rock and roll, contemporary folk music, rhythm and blues, and jazz.