A pop group, with (mainly) a set of female singers. Formulaic from the git-go (early 60s) - 3 or 4 pretty faces (sometimes only one could really sing), two gems from the Brill Building, and an ironfisted producer (e.g. Phil Spector; Sonny Bono and Cher apprenticed under him). Mucho classix resulted, but the genre lost steam when Bob Dylan and the British Invasion changed the rules. The Supremes, et al, survived it. The formula was revived decades later, following En Vogue's success.