Bluegrass is a genre of American music that originated in the Appalachian region of the United States. Common instruments used in bluegrass music include the banjo, autoharp, and guitar. The five crossword solutions for the term 'bluegrass instrument' are Banjo (5 letters), Banjos (6 letters), EARL (4 letters), Lester (6 letters), and Flatt (5 letters). Banjo and autoharp are two of the most popular instruments used in bluegrass music. EARL Scruggs and Lester Flatt were two influential bluegrass musicians who popularized the use of the banjo and guitar in bluegrass music.