The banjo is a string instrument similar to the guitar. It differs from the guitar, however, in that its resonating body is a sheet of parchment stretched over a metal hoop, and it has an open back. The banjo typically has four to six strings which pass over a low bridge and stretch over a fingerboard, which can either be fretted or unfretted. On a five string banjo, one of the strings is a melody string, known as the thumb or 5th string. The thumb string differs from the other strings on the banjo in that it is roughly three quarters to four fifths the length of the other strings, making it pitched higher than the other strings. Its tuning peg is also located along the neck of the banjo rather than on the peg head. The other strings are typically used for chordal accompaniment. Banjos can have wire strings, which are typically plucked using plectrums, or gut strings, which can be plucked with the fingers.
The banjo is believed to have originated in Africa and is commonly associated with American folk music, particularly music from the southern United States. The banjo was in use among the slaves of the southern United States and then in the 19th century became the accepted instrument of ‘Negro Minstrels’. Later, in the 20th century, it found a place in jazz bands.
Other varieties of banjo include the tenor banjo, which has a different tuning scheme resembling that of the violin family, and the smaller zither banjo which has wire strings.