Definition: Epiphany refers to an unexpected revelation or enlightenment that leads to a new understanding, especially in religion. Definition: Epiphany - an event of revelation, usually occurring during Christmas (Christmas Day is celebrated on December 25th, which also happens to be Advent, a period marking the start of Christmas). This event often involves sudden insight or realization. The most famous example occurs in the Bible where Mary Magdalene and Martha are told by the Lord that he has sent her and John the Baptist to tell them about him. Epiphany is an event that marks a major turning point in Christian teachings.