What is the ruling on naming a girl Meelia?

The basic rule for names is permissibility, except for what is forbidden by Islamic law. Non-Arabic names should not be used unless their meaning is known. If the meaning is acceptable, there is no harm, although Islamic names are preferred. There is no reliable source for the meanings of non-Arabic names, but it is common for the name (Milia) to mean: "the strong working woman," or "the toiling, striving, and successful one."