ego

Concise Oxford English Dictionary © 2008 Oxford University Press:
ego /ˈiːgəʊ, ˈɛ-/

▶noun (pl. egos)

• 1 a person's sense of self-esteem or self-importance.

• 2 Psychoanalysis the part of the mind that mediates between the conscious and the unconscious and is responsible for reality testing and a sense of personal identity. Compare with id and superego.

• 3 Philosophy (in metaphysics) a conscious thinking subject.

– derivatives
egoless adjective.

– origin C19: from L., lit. ‘I’.