Where does “Xê-un” come from?

Xê-un (Vietnamese) comes from French Séoul, from Korean 서울, from Old Korean 徐羅伐.

Ancestry of “Xê-un”, step by step

Step	Language	Word	Meaning
1	French	Séoul	—
2	Korean	서울	capital; large city
3	Old Korean	徐羅伐	—

Xê-un — Etymology, Origin & Word History | Etymology Explorer