epiphany (n.) Look up epiphany at Dictionary.com
early 14c., "festival of the manifestation of Christ to the gentiles" (celebrated Jan. 6; usually with a capital -E-), from Old French epiphanie, from Late Latin epiphania, neuter plural (taken as feminine singular), from late Greek epiphaneia "manifestation, striking appearance" (in New Testament, "advent or manifestation of Christ"), from epiphanes "manifest, conspicuous," from epiphainein "to manifest, display," from epi "on, to" (see epi-) + phainein "to show" (see phantasm).

Of divine beings other than Christ, first recorded 1660s; general literary sense of "any manifestation or revelation" appeared 1840, first in De Quincey.