Philos. the self, variously conceived as a spiritual substance on which experience is superimposed, the series of acts and mental states introspectively recognized, etc.
Psychoanalysis that part of the psyche which experiences the external world, or reality, through the senses, organizes the thought processes rationally, and governs action: it mediates between the impulses of the id, the demands of the environment, and the standards of the superego
See ego in American Heritage Dictionary 4
(ēˈgō, ĕgˈō)
nounpl.e·gos
The self, especially as distinct from the world and other selves.
In psychoanalysis, the division of the psyche that is conscious, most immediately controls thought and behavior, and is most in touch with external reality.
a. An exaggerated sense of self-importance; conceit.