The Bible (older translations) lists the name, Lucifer, only once – Isaiah 14:12. It is clearly in reference to a Babylonian king, possibly even Nebuchadnezzar. In context, it has nothing to do with Satan.
The name, Lucifer, simply means, “morning star” in Latin, a language which wasn’t even spoken in Isaiah’s time. (Interestingly enough, “Morning Star” is one of the many titles for Jesus Christ.)
Furthermore, the Bible never actually says that Satan is a fallen angel as is the popular notion. The Bible gives little definite indication that Satan is/was an angel at all. And as for being “fallen”; in the Book of Job he still is granted access to God so he obviously is not barred from Heaven. Also, Revelation implies that he has not yet been cast out. That is yet to come.
So who and/or what is Satan? His name means, “adversary”. Perhaps that best describes him, after all.
One more thing. Another common misconception is that the serpent in the Garden of Eden was Satan. The Book of Genesis nowhere supports this. All indications are that it was just an ordinary, albeit exceptionally clever, beast. (Genesis 3:1)
The one part never changed at all; the other grew and grew.
The changeless part was always true, The growing part was always new,
And I wondered, when the tale was through, Which part was me, and which was you.