Where does “Jaðarr” come from?

Jaðarr (Old Norse) comes from Old Norse jaðarr, from Proto-Germanic edaraz, from Proto-Indo-European edh-.

Ancestry of “Jaðarr”, step by step

Step	Language	Word	Meaning
1	Old Norse	jaðarr	a rim, edge, selvage; the highest one, foremost...
2	Proto-Germanic	edaraz	enclosure; shelter; border, edge, rim
3	Proto-Indo-European	edh-	—

Jaðarr — Etymology, Origin & Word History | Etymology Explorer