Well... I was reading about the Korean surname Choi.
and then it said: "Choi (Hangul: 최) is written with the Hanja character 崔, meaning "a governor who oversees the land and the mountain". The surname Choi also means 'mountain'."
Well... ATEEZ's San's surname is Choi.
and San means "Mountain"
So according to Wikipedia, Choi San is Mountain Mountain...
or maybe it is actually "Governor-who-oversees-the-land-and-the-mountain Mountain."
But Mountain Mountain sounds funnier.