sweet Adeline
n.— «What is Barber Shop? It’s like a group of four parts, sung a cappella. Boy groups are called Barber Shops; girl groups are called Sweet Adelines.» —“Geek of the Week: Jenny Mack, Junior: Biochemical Engineering” by Benjamin Johnson in Colorado School of Mines Oredigger (Golden, Colorado) Jan. 19, 2009. (source: Double-Tongued Dictionary)
Male Barbershop harmony singers are known as Barbershoppers, ladies as Sweet Adelines. They are members of the two international organizations, the Barbershop Harmony Society and Sweet Adelines International, as well as a smaller women’s society called Harmony Incorporated. There are over 50,000 Barbershop singers in the US and Canada, with many affiliate groups around the world. Do a web search for “Barbershop Harmony” for more information.