Aristotle thinks everyone will agree that the terms “eudaimonia” (“happiness”) and “eu zên” (“living well”) designate such an end. The Greek term “eudaimon” is composed of two parts: “eu” means “well” and “daimon” means “divinity” or “spirit.” To be eudaimon is therefore to be living in a way that is well-favored by a god. But Aristotle never calls attention to this etymology in his ethical writings, and it seems to have little influence on his thinking. He regards “eudaimon” as a mere substitute for eu zên (“living well”). - http://plato.stanford.edu/entries/aristotle-ethics/