A stranger is any person personally unknown to the actor of reference.

Evidence

By stranger I refer to any person who is personally unknown to the actor of reference. Thus, as we have seen, while a celebrity is personally known to many persons, the majority of these are not personally known to him. In this sense, to all of us most of the world’s three billion people are strangers. — Lyn H. Lofland, World of Strangers_ Order and Action in…, 109

Categorization

• DEFINE: Core operative definition of ‘stranger’ for the whole book — defined relationally, not demographically.