ˈmithrəˌizəm noun
( -s )
Usage: usually capitalized
Etymology: Mithras, Persian god of light (from Latin, from Greek) + English -ism
: an oriental mystery cult incorporating elements from Zoroastrianism, the primitive religions of Asia Minor, and Hellenism, having as its deity Mithras, the savior hero of Persian myth, admitting only men to its seven degrees of initiation, and constituting a serious rival of Christianity in the Roman Empire between the second and fourth centuries A.D.