Where does “Leteo” come from?

Leteo (Spanish) comes from Latin Lethaeus, from Ancient Greek ληθαῖος.

Ancestry of “Leteo”, step by step

Step	Language	Word	Meaning
1	Latin	Lethaeus	of or pertaining to Lethe, Lethean; of the...
2	Ancient Greek	ληθαῖος	—