ego

• n. 自我；うぬぼれ；自意識
• n.(エゴ)人の名前;(日本)イドゥ(姓);(F)エゴ.

英語のIの原型であるラテン語から。

ego

ego: [19] Ego is Latin for ‘I’ (and comes in fact from the same Indo-European base as produced English I). English originally acquired it in the early 19th century as a philosophical term for the ‘conscious self’, and the more familiar modern uses – ‘self-esteem’, or more derogatorily ‘selfimportance’, and the psychologist’s term (taken up by Freud) for the ‘conscious self’ – date from the end of the century.

Derivatives include egoism [18], borrowed from French égo?sme, and egotism [18], perhaps deliberately coined with the t to distinguish it from egoism. And the acquisitions do not end there: alter ego, literally ‘other I, second self’, was borrowed in the 16th century, and the Freudian term superego, ‘beyond I’, entered the language in the 1920s.
=> i

ego (n.)

1714, as a term in metaphysics, "the self; that which feels, acts, or thinks," from Latin ego "I" (cognate with Old English ic; see I). Psychoanalytic (Freudian) sense is from 1894; sense of "conceit" is 1891. Ego-trip first recorded 1969, from trip (n.). Related: egoical; egoity.

In the book of Egoism it is written, Possession without obligation to the object possessed approaches felicity. [George Meredith, "The Egoist," 1879]

1. She is，first and foremost，her husband 's alter ego .

彼女はまず夫の知己である。

2.Barry Humphries 's alter ego Dame Edna has taken the US by storm.

バリー?ハンフリーはエドナ夫人役で全米を騒がせた。

3.She was a prisoner of her own ego .

彼女は自分のプライドに困っている。

4.Superman 's alter ego was Clark Kent.

スーパーマンの2番目の自己はクラーク？ケント。

5.He has the biggest ego of anyone I 've ever met.

彼は私が見た中で最も自負している人です。