Where does “Phlegethon” come from?

Phlegethon (Latin) comes from Ancient Greek Φλεγέθων, from Ancient Greek φλέγω, from Proto-Indo-European bʰel-, from Proto-Indo-European bʰōl-.

Ancestry of “Phlegethon”, step by step

Step	Language	Word	Meaning
1	Ancient Greek	Φλεγέθων	—
2	Ancient Greek	φλέγω	I set on fire, burn, scorch; I kindle, arouse,...
3	Proto-Indo-European	bʰel-	to sound; to speak, roar, bark; shiny, white; to...
4	Proto-Indo-European	bʰōl-	—

Phlegethon — Etymology, Origin & Word History | Etymology Explorer