“O day star, son of the dawn”
How you have fallen from heaven, O day star, son of the dawn! You have been cut down to the ground, O destroyer of nations. (Isaiah 14:12 BSB)
What it sounds like today
A direct reference to Satan by the name Lucifer.
The cultural key
This is the source of the name 'Lucifer,' but the passage is not, in its setting, about the devil. 'Day star, son of the dawn' translates Helel ben Shachar, the morning star, the planet Venus blazing at dawn only to be swallowed by the rising sun. Isaiah 14 is explicitly a mocking funeral-song 'against the king of Babylon' (14:4), and it borrows a Canaanite myth in which a minor god, the Morning Star, tried to ascend and enthrone himself above the other gods and was cast down. The prophet turns that story on the proud Babylonian tyrant: you reached for heaven, and you have crashed to the grave like the morning star outshone by dawn. The Latin Vulgate translated 'day star' as lucifer ('light-bringer'), and later Christian tradition read the verse as the fall of Satan, but its plain sense is the toppling of an arrogant human empire. The modern reader hears 'Lucifer' and thinks only of the devil, missing the taunt against Babylon.
Recovered meaning
'Day star, son of the dawn' is the morning star, and the verse is a taunt against the fallen king of Babylon, drawing on a myth of a god who tried to scale heaven and fell. 'Lucifer' comes from the Latin here; the later devil-reading is an overlay on a jeer at a human tyrant.