n.1. generally, a state of cordial relations between individuals or groups. 2. in the theory of separation–individuation of Hungarian-born U.S. child psychoanalyst Margaret Schönberger Mahler (1897–1985), a subphase, after about 18 months of age, in which the child makes active approaches to the mother. This contrasts with the preceding subphase in which the child struggles with the first efforts of psychological individuation from the mother.