alter ego

Where does the word "alter ego" come from? It comes from Latin alter ego, and was adopted directly into English (1500s).

Alter ego’s story begins in Latin: alter ego meant “other self.” Other self, from alter (other) and ego (I, self). It reached English by 1500s as alter ego. Cicero used it for a trusted friend, 'a second self'. Today, alter ego means a second self, or a different version of one's personality.

1. Stage 1 · Latin · ancient alter ego "other self", other self, from alter (other) and ego (I, self).
2. Stage 2 · English · 1500s alter ego "a second, often very different side of one's personality", Cicero used it for a trusted friend, 'a second self'.