ma·gi [māˌjī] n. pl n sing ma·gus 1. (Non-Christian) the Zoroastrian priests of the ancient Medes and Persians. 2. (Christian) the wise men from the East who came to do homage to the infant Jesus (Matthew 2:1-12) and traditionally called Caspar, Melchior, and Balthazar.
Synonyms: Wise Men, sage, seer
Etymology: c.1200, "skilled magicians, astrologers," from Latin magi, plural of magus "magician, learned magician," from Greek magos, a word used for the Persian learned and priestly class as portrayed in the Bible (said by ancient historians to have been originally the name of a Median tribe), from Old Persian magush "magician" (see magic). Related: Magian.
This one is interesting to me, because being an old D&D'er, I always thought Magi was just another word for Wizard.