The banjo is a stringed musical instrument. It is an American development of African origins related to the Kora etc., but with a guitar type neck. Found with 4, 5, 6, 7 and 8 or more strings, popular types are the 5 string, Tenor (4 string), Plectrum (long neck 4 string), Banjolele (Ukulele Banjo), Banjolin (Mandolin Banjo).
The banjo evolved among the negro slaves of North America and was originally a six-stringed instrument with a body like a tambourine and a neck like a guitar. The banjo is played by stopping the strings with the fingers of the left hand and twitching or striking them with the fingers of the right. The upper or octave string, however, is never stopped. Research Banjo
In music, on a string instrument, the ridge at one end of the fingerboard, next to the peg box, which raises the strings from the surface of the fingerboard is called a nut. On some instruments, such as the ukulele, there is a movable nut, which raises the pitch of the entire instrument. The term ' nut' is also applied to the part of a bow which secures the horsehair and, by incorporating a screw mechanism, allows the tension of the hairs to be adjusted. Research Nut