Barbershop vocal harmony is a style of a cappella (unaccompanied by any instrumentation) close harmony characterized by four parts for every note where the sounds for each note are usually the same in all parts.  The names of the four parts, even when arranged for women's voices, are Tenor, Lead, Baritone, and Bass.  Each of the four parts has its own role: generally the lead sings the melody, the tenor harmonizes above the melody, the bass sings the lowest harmonizing notes, and the baritone completes the chord, usually below the lead.

Barbershop music is usually performed by a barbershop quartet, or a four part barbershop chorus.

One of the hallmark features of the barbershop style is that barbershop music features songs that are understandable to it's audience. Because of that, barbershop music is not constrained by strict note time values, but, especially in slower ballads, is subject to the interpretation of the Director in conveying the meaning of the lyrics.