A standard five-string banjo has five strings.
The short fifth string, called the drone string, begins partway up the neck rather than at the headstock. It usually sounds at a higher pitch than the other four strings and is a defining feature of the common American banjo.
The banjo developed from instruments brought to the Americas by enslaved West Africans, whose musical traditions influenced its early construction and playing techniques. Modern banjos have several forms, including four-string tenor and plectrum banjos, so the word “banjo” does not always mean a five-string instrument.
The five-string banjo is especially associated with old-time music and bluegrass. Its characteristic sound comes from a stretched membrane head, a resonator or open-back body, and the interaction between picked strings and the vibrating head.