f(x) is a four-member (originally five-member) South Korean girl group formed by SM Entertainment active from 2009 to 2016. The name is a play on the mathematical notation for function, with "f" signifying "flower" and "x" representing the female's double X chromosome. The group made their debut on September 1, 2009 with release of a digital single "๋ผ์ฐจํ (LA chA TA)". The group was initially composed of ๅฎ่ (Victoria), ์ ๋ฒ (Amber/Amber Liu), ๋ฃจ๋ (Luna), ์ค๋ฆฌ (Sulli) and ํฌ๋ฆฌ์คํ (Krystal). Read more on Last.fm