Omen

n. [Lat. omen, but, according to Varro, it was originally osmen, that which is uttered by the mouth, denoting wish or vow, and with him agree Festus and Nonius, says Vossius. Cicero assigns to the word the same origin as Varro. “Voces hominum, quæ vocent omĭna.” But the word came afterward to denote things rather than words. Omen is, perhaps, for obmen, from the Gr. root ὀπ, fut. ὄψομαι, to see.] An occurrence supposed to signify or portend some future event; a sign or indication; a prognostic; a presage; an augury.

Bid go with evil omen, and the brand Of infamy upon my name. Milton.