(1) A sum of the attitudes, feelings, memories, traits, and behavioral predispositions that make up the personality. (2) The individual person as represented in his or her own awareness and in his or her environment. (3) A generalized, everyday term for ego or persona. (4) In immunology, an individual's autologous cell components as contrasted with non-self, or foreign, constituents; the basic mechanism underlying recognition of self from non-self is unknown, but serves to protect the host from an immunologic attack on the host's own antigenic constituents, as opposed to immune system destruction or elimination of foreign antigens.