Where does “[[júr]], [[júgr]]” come from?

[[júr]], [[júgr]] (Old Norse) comes from Proto-Indo-European h₁ówHdʰr̥ — udder.

Ancestry of “[[júr]], [[júgr]]”, step by step

Step	Language	Word	Meaning
1	Proto-Indo-European	h₁ówHdʰr̥	udder

[[júr]], [[júgr]] — Etymology, Origin & Word History | Etymology Explorer