Where does “Arieșeni” come from?

Arieșeni (English) comes from Romanian Arieșeni, from Hungarian -eni, from Hungarian -é-, from Hungarian -d, from Middle Welsh -nt — 3rd person plural verb ending.

Ancestry of “Arieșeni”, step by step

Step	Language	Word	Meaning
1	Romanian	Arieșeni	—
2	Hungarian	-eni	Used to form the infinitive; "For the other...
3	Hungarian	-é-	—
4	Hungarian	-d	your; Used in the second-person singular definite...
5	Middle Welsh	-nt	3rd person plural verb ending

Every word from Middle Welsh -nt →Every word from Hungarian -d →Every word from Hungarian -eni →