The words of appropriation and Aneignung as used in ordinary language are ambiguous and not appropriate terms for psychological use. The psychological term of appro priation, however, has so far been largely restricted to Marxist literature. The historical background of the anthropological usage of the concept of appropriation is described, its usage in psychology clarified. The structure of appropriation as yielded by a conceptual analysis serves to evaluate the appropriateness of this term in psychologic al studies of the built environment.