The self and the ego.
Freud intentionally used Das Ich to refer to both the "self" and an abstract metapsychological system. In English, the separation of the terms "self" and "ego" has led to major problems. The word self, taken in its everyday sense, is necessarily ubiquitous in psychoanalysis. But its reflexive nature makes it impossible to define except as a series of fantasies. Self has no other place as a theoretical word. What the analysand calls his self the analyst calls ego, which is definable, either in the sense of what can be known about the analysand's experience, or as a nonexperiential abstraction.
D004532:Ego; D006801:Humans; D009289:Narcissism; D011574:Psychoanalytic Theory; D011575:Psychoanalytic Therapy; D012649:Self Concept