Lucifer (aka Satan) is the King James Version rendering of the Hebrew word הֵילֵל in Isaiah 14:12. This word, transliterated hêlēl or heylel, occurs only once in the Hebrew Bible and according to the KJV-influenced Strong's Concordance means "shining one, morning star, Lucifer". The word Lucifer is taken from the Latin Vulgate, which translates הֵילֵל as lucifer, meaning "the morning star, the planet Venus" (or, as an adjective, "light-bringing"). The Septuagint renders הֵילֵל in Greek as ἑωσφόρος (heōsphoros), a name, literally "bringer of dawn", for the morning star. (In spite of the unanimous testimony of published texts of the Septuagint, Kaufmann Kohler says that the Greek Septuagint translation is "Phosphoros".)
Before the rise of Christianity, the pseudepigrapha of Enochic Judaism, the form of Judaism witnessed to in 1 Enoch and 2 Enoch, which enjoyed much popularity during the Second Temple period, gave Satan an expanded role, interpreting Isaiah 14:12-15, with its reference to the morning star, as applicable to him, and presenting him as a fallen angel cast out of heaven. Christian tradition, influenced by this presentation, came to use the Latin word for "morning star", lucifer, as a proper name ("Lucifer") for Satan as Satan was before his fall. As a result, "Lucifer has become a by-word for Satan in the Church and in popular literature", as in Dante Alighieri's Inferno and John Milton's Paradise Lost.