Where does “petroleum” come from?

petroleum (Medieval Latin) comes from Latin oleum, from Ancient Greek ἔλαιον, from Ancient Greek ἐλαία, from Proto-Hellenic elaíwā, from Proto-Indo-European loiwom.

Ancestry of “petroleum”, step by step

petroleum traces back through 3 separate lines of ancestry.

via Latin oleum

Step	Language	Word	Meaning
1	Latin	oleum	olive oil; the palaestra
2	Ancient Greek	ἔλαιον	olive oil, commonly used as an anointing oil; any...
3	Ancient Greek	ἐλαία	olive tree; olive; naevus
4	Proto-Hellenic	elaíwā	—
5	Proto-Indo-European	loiwom	—

via Latin petra

Step	Language	Word	Meaning
1	Latin	petra	stone, rock
2	Ancient Greek	πέτρα	rock formation: cliff, ledge, cave, ridge; stone

via Ancient Greek πετρέλαιον

Step	Language	Word	Meaning
1	Ancient Greek	πετρέλαιον	oil of the rock

Words derived from “petroleum”

Every word from Proto-Indo-European loiwom →Every word from Proto-Hellenic elaíwā →Every word from Ancient Greek ἐλαία →