An expatriate is someone who lives in another country by choice. If you leave your split-level ranch in Ohio and move to a writers' commune in Paris for good, you've become an expatriate.
Expatriate can also be a verb, so that American in Paris has expatriated. There was a scene of expatriates, or expats, living in Paris in the roaring '20s that included writers like F. Scott Fitzgerald and Gertrude Stein. The word used to mean to get kicked out of your native country — it's from the French word expatrier which means "banish." The prefix ex means "out of" and the Latin patria "one's native country," but the word took a turn and now refers to people who left without getting shoved out.
