Are Lucifer and Satan different beings?

Q. "Are Lucifer and Satan different beings?"

A. Satan filled the king of Babylon with the ambition to have complete domination over the earth, even over “Jehovah’s throne” (1Ch 29:23) and “the stars of God,” the kings of the line of David sitting on the throne at Mount Moriah (by extension, Zion).

This “king,” that is, the dynasty of Babylon, ‘lifted himself up’ in his own heart and was in his own eyes and in the eyes of his admirers a “shining one,” a “son of the dawn.” (In some Bible translations the Latin Vulgate term “Lucifer” is retained. It is, however, merely the translation of the Hebrew word heh·lel′, “shining one.” Heh·lel′ is not a name or a title but, rather, a term describing the boastful position taken by Babylon’s dynasty of kings of the line of Nebuchadnezzar.) (Isa 14:4-21) Since Babylon was a tool of Satan, its “king” reflected Satan’s own ambitious desire.

NOTE: This answer represents the Jehovah's Witnesses perspective.

I know this is an older question, but since there was no selected answer, I thought I'd give it a go. The answer is going to depend a lot on the denomination that is answering, so I will approach this from a purely non-biased, non-denominated, purely Scriptural point of view.

Now, are Lucifer and Satan the same being? Yes and no.

As an adjective, the Latin word lucifer means "light-bringing" and was applied to the moon. As a noun, it meant "morning star", or in poetry, "day". This word, being Latin, actually should not exist in English translations, and should actually be translated into one of the above options. This word is a Latin translation of הֵילֵל, read as hêlêl or heylel.

Isaiah 14:12 is not the only place where the Vulgate uses the word "lucifer". It uses the same word four more times, in contexts where it clearly has no reference to a fallen angel: 2 Peter 1:19 (meaning "morning star"), Job 11:17 ("the light of the morning"), Job 38:32 ("the signs of the zodiac") and Psalms 110:3 ("the dawn"). To speak of the "morning star", lucifer is not the only expression that the Vulgate uses: three times it uses stella matutina: Sirach 50:6 (referring to the actual morning star), and Revelation 2:28 (though this might actually use the word "lucifer" or "lux ferre") and 22:16 (referring to Jesus).

Another fun little note is that the Exsultet includes "lucifer" in clear description of Jesus Christ. Use of "Lucifer" as a names popularized by Dante Alighieri's Inferno and John Milton's Paradise Lost.

In regards to Isaiah 14:12, translating the actual line gives us "Hillel ben-Shahar", which very well could have been the name of Babylon's King, being that Hebrew contains no indications for capitalization.

Now for Satan:

Satan comes from the Hebrew word שָּׂטָן (pronounced "satan"), meaning "adversary", "accuser", or "enemy". The original Hebrew term is a noun/verb meaning “obstruct, oppose,”. It is almost always accompanied by the prefix "ha-" in Hebrew, meaning "the" in English - thus "the adversary", "the accuser", etc.

So back to the question, are Lucifer and Satan the different beings?

Yes and no.

Lucifer, whether Isaiah was writing about the Devil or not, was clearly an enemy of God and His people - so he would have been "ha-Satan", the enemy. If Lucifer is in fact the Devil, he is both the enemy by the Hebrew definition and Satan as we know him.

Lucifer is a transliteration of the name Morningstar used in the Latin Vulgate. Satan was referred to the Morningstar several times in the Bible. Wikipedia has a good explanation of where the these terms are used in the Bible and what the various contexts are.

We know that the being who is Satan was one of the chief angels who decided he would rather have the glory for himself that God had reserved as His own.

While the exorcist may have met demons with various names, we know demons are primarily invested in lying, and so I would take what the exorcist claimed with a grain of salt.

The name "Lucifer" appears only once in the Bible, in Isaiah (KJV), where he alludes to the tale (which we can assume is already known to his Jewish audience at that time) of the great Lucifer having fallen from heaven, being cast down and looked upon with contempt, in order to draw a parallel to the king of Babylon and his kingdom's impending fall.

Lucifer means "morning star", which is used various times and in various ways in the Bible, including by Christ to refer to himself at one point in Revelation. But see Job 38 (RSVCE), where it says that when the foundations of the world were laid, "the morning stars sang together, and all the sons of God shouted for joy." I think this is the closest we have in the Bible to a passage equating Lucifer with an angel.

It's important to note that both of these passages are highly poetic in nature, as is the third, the story of the Dragon in Revelation, who is cast out of heaven and makes war with the Church, who is equated to Satan. If the dragon cast out of heaven is the same as Lucifer the Morning Star cast out of heaven, then he is Satan. But it's difficult to say anything for certain, going only on Biblical authority.