Barbershop quartet

A barbershop quartet is a group of four singers who sing music in the barbershop style, characterized by four-part harmony without instrumental accompaniment (a cappella). The four voices that make up a quartet are the lead, the bass, the tenor, and the baritone. Barbershop music is typified by close harmony—the upper three voices generally remain within one octave of each other.

Historically, barbershop quartets were mainly sung by male singers; contemporary quartets can include any gender combination. All-female barbershop quartets were often called beauty shop quartets, a term that has fallen out of favor.

While the regional origins of barbershop quartet singing are not wholly agreed upon, current organizations that promote the style typify it as an "old American institution." Though the style is most popular in the United States, barbershop organizations exist in the United Kingdom, the Netherlands, Germany, France, Spain, Italy, Ireland, South Africa, Finland, Sweden, Denmark, New Zealand, Australia, and Canada.

Barbershop quartets have been featured in popular culture in musical theater productions such as The Music Man, and lampooned in television series such as The Simpsons and Family Guy.