boundary /boun″dərē/ , 1. (in psychology) an ability to separate the self from others, setting personal boundaries that help maintain one’s self-image and self-concept. 2. in social psychology, the ability to separate self from others in interpersonal relationships in a way in which all parties share but are uniquely individual and respectful. 3. a professional boundary in which a professional is able to maintain a professional self that is separate from the client, patient, or the patient’s significant others.