from
The Collaborative International Dictionary of English v.0.48
ego \e"go\, n.; pl. {egos}. [L., I.]
The conscious and permanent subject of all psychical
experiences, whether held to be directly known or the product
of reflective thought; the subject consciously considered as
"I" by a person; -- opposed to {non-ego}.
[1913 Webster +PJC]
2. (Psychoanalysis) that one of the three parts of a person's
psychic apparatus that mediates consciously between the
drives of the id and the realities of the external
physical and social environment, by integrating
perceptions of the external world and organizing the
reactions to it. Contrasted with the {id} and {superego}.
[PJC]
3. egotism; as, a job requiring a diplomat without too much
ego.
[PJC]
4. self-esteem; as, he has an overinflated ego.
[PJC]