Where does “더럼” come from?

더럼 (Korean) comes from English Durham, from Old English Dunholm, from Old English holm, from Old Norse hólmr, from Proto-Germanic hulmaz, from Proto-Indo-European kl̥Hmos, from Proto-Indo-European ḱelH- — to freeze.

Ancestry of “더럼”, step by step

Step	Language	Word	Meaning
1	English	Durham	One of a breed of short-horned cattle,...
2	Old English	Dunholm	—
3	Old English	holm	ocean, sea, waters
4	Old Norse	hólmr	island
5	Proto-Germanic	hulmaz	small island, hill, mound
6	Proto-Indo-European	kl̥Hmos	—
7	Proto-Indo-European	ḱelH-	to freeze

Every word from Proto-Indo-European ḱelH- →Every word from Proto-Indo-European kl̥Hmos →Every word from Proto-Germanic hulmaz →