Where does “Ender” come from?

Ender (Turkish) comes from Ottoman Turkish اندر, from Arabic أَنْدَر — rarer, rarest.

Ancestry of “Ender”, step by step

Step	Language	Word	Meaning
1	Ottoman Turkish	اندر	—
2	Arabic	أَنْدَر	rarer, rarest

Ender — Etymology, Origin & Word History | Etymology Explorer