CSR (Korean: 첫사랑) is a seven-member South Korean girl group formed and managed by A2Z Entertainment. CSR is an abbreviation for the Korean word "첫사랑" (Cheotsarang), which means "First Love". The group consists of the members Sua, Geumhee, Sihyeon, Seoyeon, Yuna, Duna, and Yeham. The group is composed entirely, during the debut, of 17-year-olds (2005) under the Korean age system, a first time in the industry. The company stated on the name that, "taking advantage of all members being seventeen years old, the group plans to show various interpretations of first love and tell the story of the members growing up year by year". CSR's fandom name is MAEUM (마음) , meaning heart. The meaning of the group, as said by the leader Sua is: "I think first love is a word that will be remembered for a long time. Which we want to be in people’s memories for a long time. Everyone has a lot of love at first sight. We therefore named it with the desire to become a memorable group for a long time." They debuted on July 27, 2022 with the track Pop? Pop! from their debut extended play Sequence : 7272. On November 17, 2022, they released their first single album Sequence : 17& and the title track LOVETICON (♡TiCON). On March 29, 2023, CSR released their second EP Delight and the title track Shining Bright. On November 26, 2023, the group released a special digital single HBD To You (Midnight Ver.), as commemoration of the first anniversary of the group's fandom, Maeum. On June 11, 2024, the group released their second single album L'heure Bleue : Prologue, with its lead single Pretty Mob. This marked a year and 3 months after their previous comeback. In addition, the group released their first Japanese extended play, titled L'heure Bleue, on July 3, 2024.