A cappella is generally believed to mean voices without instrumental accompaniment. The term is actually of Italian derivation, translating literally as "in the chapel style." In its original usage, it referred to the singing done in church without instrumental accompaniment.
Within a modern context, a cappella is generally associated with the doo-wop tradition of the 1950s and early 1960s. The first hits in this style were recorded by a New Haven-based group, the Nutmegs, in 1955: "Story Untold" and "Ship of Love." Once doo-wop proved its commercial potential, the record labels which possessed sufficient financial resources began employing instrumental backups during studio sessions. As a result, by the late 1950s, a cappella was limited to amateur groups who practiced largely on street corners and in apartment hallways.
Since the late 1960s, the genre has become associated almost exclusively with two acts, the Persuasions--whose albums have included A cappella (1968), Street Corner Symphony (1972), and Chirpin' (1977)--and 14 Karat Soul. The Black Contemporary group, Boyz II Men, revived interest in the genre by utilizing its conventions on a string of hit singles in the early 1990s.