A fallen angel is a wicked or rebellious angel that has been cast out of heaven. The term "fallen angel" does not appear in the Bible, but it is used of angels who sinned, such as those referred to in 2 Peter 2:4, "For if God did not spare angels when they sinned, but cast them into hell and committed them to chains of gloomy darkness to be kept until the judgment ..."; of angels cast down to the earth in the War in Heaven; of Satan; demons, or of certain Watchers. The term has become popular in fictional literature regarding angels.
Mention of angels who descended to Mount Hermon (not "fell" to Earth) is found in the Book of Enoch, which the Ethiopian Orthodox Church and Eritrean Orthodox Tewahedo Church accept as canonical, as well as in various pseudepigrapha.