Where does “CEO” come from?

CEO (Portuguese) comes from Proto-Celtic *kiwos, from Proto-Indo-European (s)ḱih₃-wó-s, from Proto-Indo-European (s)ḱeh₃- — darkness, shadow.

CEO (Portuguese): Superseded spelling of céu

Definitions

Step	Language	Word	Meaning
1	Proto-Celtic	*kiwos	—
2	Proto-Indo-European	(s)ḱih₃-wó-s	—
3	Proto-Indo-European	(s)ḱeh₃-	darkness, shadow

CEO — Etymology, Origin & Word History | Etymology Explorer