Where does “Tartessos” come from?

Tartessos (Latin) comes from Ancient Greek Ταρτησσός, from Ancient Greek Ἡράκλειοι Στῆλαι.

Ancestry of “Tartessos”, step by step

Step	Language	Word	Meaning
1	Ancient Greek	Ταρτησσός	—
2	Ancient Greek	Ἡράκλειοι Στῆλαι	—

Tartessos — Etymology, Origin & Word History | Etymology Explorer