from Wiktionary, Creative Commons Attribution/Share-Alike License
- adj. Of or relating to the Roman Mysteriae Mithrae ("Mysteries of Mithras", "Mithraic Mysteries"), an astrology-centric, middle-platonic mystery cult of the 1st-4th century Roman Empire that claimed to have been founded by "Zoroaster".
Mithras + -ic. First attested in English circa 1678. More at Mithras (Wiktionary)