A banjo is a stringed instrument with a thin membrane, made of plastic or animal skin, stretched over a frame to form a resonator. It was originally used in African-American traditional music and the folk culture of rural whites, later it was frequently used in traditional jazz.
There are two techniques: “rolls” and “drones”, associated with the banjo. They are idiomatic to the music instrument in all styles, and their sound is characteristic of bluegrass. Roll is a right-hand fingering pattern and consists of 8 notes. Drones are quick little notes, which are played on the string.