Where does “A-ten” come from?

A-ten (Vietnamese) comes from French Athènes, from Latin Athenae, from Ancient Greek Ἀθῆναι, from Ancient Greek Ἀθήνη — Athene; Athena.

Ancestry of “A-ten”, step by step

Step	Language	Word	Meaning
1	French	Athènes	—
2	Latin	Athenae	Athens
3	Ancient Greek	Ἀθῆναι	Athens
4	Ancient Greek	Ἀθήνη	Athene; Athena