Lucifer is not the same as Satan in the Bible, although in modern usage, the two names are often used interchangeably. The name "Lucifer," which means roughly "Morning Star," was used only once in the King James Bible; in the ASV Bible, the term "Day Star" is used instead.
The sole use of the name Lucifer is found in Isaiah 14:12 where it refers to someone who has "fallen from heaven." Though Satan was cast out of Heaven, the name Lucifer actually refers to the king of Babylon who is the subject of most of that chapter. Because Babylon is east of the Levant, it would be entirely understandable to refer to its king as the morning star.