The New Dictionary of Cultural Literacy, Third Edition. 2002.
barbershop singing
A style of singing in parts for small groups, usually four singers of the same sex (“barbershop quartets”). The notes sung by the voices are usually close to each other in pitch, resulting in “tight” chords, or “close” harmony.
‡ Barbershop singing flourished in the early twentieth century in the United States, and barbershop groups today often prefer the songs from that period, including “Sweet Adeline” and “The Sweetheart of Sigma Chi.”
