If you dream of a visitor, then you are being reacquainted with a foreign part of yourself that you are in the process of integrating. Consider the qualities of this visitor.
If you dream of being a visitor, then you are courageously exploring new terrain and are curiously open to learning new ways of thinking and being. Alternatively, you may be feeling that your space is being invaded energetically, physically, or psychically. Consider the feeling tone of this dream to discern the significance. See Alien.... Strangest Dream Explanations