You know with Oil or Thana, its not actually pronounce Oil as in petrol na lol but I don't know how the heck we end up spelling it 'OIL'
Sometimes the nick names that the stars have the directors or the person who made them into a star gives it to them, like I heard Aum Patchrapa, her nick name Aum was given to her by her manager or something before she became famous because her last nick name was kind of dull lol. Along with Poo (which means crab) lol, her last name is a stage last name... therefore changed purposely by her boss etc so that's how some of them got their nicknames or name.