The term "Lucifer" comes from the Latin Vulgate, not the Hebrew Bible
In the Old Hebrew timeline before 1 BC, without Greek influence, "Lucifer" as a name or concept does not exist in Hebrew scriptures.
The term comes from the Latin Vulgate translation of Isaiah 14:12, where Jerome used lucifer (meaning "light-bearer" or "morning star") to translate the Hebrew word הֵילֵל (Helel).
The first known use of "Lucifer" as a translation of Helel (הֵילֵל) in Isaiah 14:12 appears in the Latin Vulgate, translated by Saint Jerome around 382–405 AD.
The passage in Isaiah was understood as a human king's arrogance and downfall, not as a reference to a rebellious angel.
The Hebrew word הֵילֵל (Helel) appears only once in the entire Hebrew Bible—Isaiah 14:12—where it describes the fall of a proud ruler:
"How you have fallen from heaven, O Helel ben Shachar (הֵילֵל בֶּן־שָׁחַר), you who once laid low the nations!" (Isaiah 14:12)