The banjo is a stringed instrument with, typically, four or five strings, which vibrate a membrane of plastic material or animal hide stretched over a circular frame. Simpler forms of the instrument were fashioned by enslaved Africans in Colonial America, adapted from several African instruments of the same basic design.
The banjo is usually associated with country, folk, classical music, Irish traditional music and bluegrass music. Historically, the banjo occupied a central place in African American traditional music, before becoming popular in the minstrel shows of the 19th century. In fact, African Americans influenced early development of the music that became country and bluegrass, through the introduction of the banjo and through the innovation of musical techniques for both the banjo and fiddle. The banjo, with the fiddle, is a mainstay of American old-time music.
Recently, the banjo has enjoyed inclusion in a wide variety of musical genres, including pop crossover music, indie rock and Celtic punk.
The modern banjo comes in a variety of forms, including four- and five-string versions. A six-string version, tuned and played similarly to a guitar, has gained popularity. In almost all of its forms, banjo playing is characterized by a fast arpeggiated plucking, though there are many different playing styles.
The body, or “pot”, of a modern banjo typically consists of a circular rim (generally made of wood, though metal was also common on older banjos) and a tensioned head, similar to a drum head. Traditionally the head was made from animal skin, but today is often made of various synthetic materials. Most modern banjos also have a metal “tone ring” assembly that helps further clarify and project the sound, however many older banjos did not include a tone ring
The banjo is usually tuned with friction tuning pegs or planetary gear tuners, rather than the worm gear machine head used on guitars. Frets have become standard since the late 19th century, though fretless banjos are still manufactured and played by those wishing to execute glissando or otherwise achieve the sound and feeling of early playing styles.
Modern banjos are typically strung with metal strings. Usually the fourth string is wound with either steel or bronze-phosphor alloy. Some players may string their banjos with nylon or gut strings to achieve a more mellow, old-time tone.