Where does “သဳလ” come from?

သဳလ (Mon) comes from Pali sīla, from Sanskrit शील, from Sanskrit शी, from Proto-Indo-European ḱey- — to be lying down; to settle.

သဳလ (Mon): morals or precepts {which are five, eight, and ten in number} codifying moral conduct of which ten are followed by monks, five ordinarily by laymen, and eight by white-robed acolytes (လၟာတ်) and ဗြဴမိန် (female renunciants) and by laymen as sabbath or Lenten observance