Ego

Ego is a Latin word meaning "I", cognate with the Greek Εγώ (Ego) meaning "I", often used in English to mean the "self", "identity" or other related concepts.

H. P. Blavatsky defined it as follows:

Ego (Lat.). “Self”; the consciousness in man “I am I”—or the feeling of “I-am-ship”. Esoteric philosophy teaches the existence of two Egos in man, the mortal or personal, and the Higher, the Divine and the Impersonal, calling the former “personality” and the latter “Individuality Egoity. From the word “Ego”. Egoity means “individuality”, never “personality”, and is the opposite of egoism or “selfishness”, the characteristic par excellence of the latter.