Girls' Generation is composed of people.
A girl group is a music act featuring several female singers who generally harmonize together . Girls ' Generation , also known as SNSD , is a South Korean girl group formed by S.M. Entertainment . The group is composed of eight members : Taeyeon , Sunny , Tiffany , Hyoyeon , Yuri , Sooyoung , Yoona , and Seohyun . Kim Hyo-yeon ( born September 22 , 1989 ) , better known mononymously as Hyoyeon , is a South Korean singer and television personality . Kwon Yu-ri ( born December 5 , 1989 ) , better known by the mononym Yuri , is a South Korean singer and actress .