"second self, counterpart," 1530s, a Latin phrase (used by Cicero), "a second self, a trusted friend" (compare Greek allos ego); see alter and ego.
Entries linking to alter ego
alter v.
late 14c., "to change (something), make different in some way," from Old French alterer "to change, alter," from Medieval Latin alterare "to change," from Latin alter "the other (of the two)," from PIE root *al- (1) "beyond" + comparative suffix -ter (as in other). Intransitive sense "to become otherwise" first recorded 1580s. Related: Altered; altering.
ego n.
by 1707, in metaphysics, "the self; that which feels, acts, or thinks," from Latin ego "I" (cognate with Old English ic; see I); its use is implied in egoity.
They that have pleaded against Propriety, and would have all things common in this World, have forgotten that there is a Propriety, in our present Egoity, and Natural Constitution, which rendereth some accidental Propriety necessary to us (etc.) ["The Practical Works of the Late Reverend and Pious Mr. Richard Baxter," London, 1707]
Psychoanalytic (Freudian) sense is from 1894; sense of "conceit" is 1891. Ego-trip first recorded 1969, from trip (n.). Related: egoical.
In the book of Egoism it is written, Possession without obligation to the object possessed approaches felicity. [George Meredith, "The Egoist," 1879]