Where does “Alfarheimr” come from?

Alfarheimr (Old Norse) comes from Old Norse heimr, from Proto-Germanic haimaz, from Proto-Indo-European ḱóymos, from Proto-Indo-European ḱey- — to be lying down; to settle.

Ancestry of “Alfarheimr”, step by step

Alfarheimr traces back through two separate lines of ancestry.

via Old Norse heimr

Step	Language	Word	Meaning
1	Old Norse	heimr	realm, region within walking distance to a þing...
2	Proto-Germanic	haimaz	home; house; village
3	Proto-Indo-European	ḱóymos	of the home, belonging to the family; village,...
4	Proto-Indo-European	ḱey-	to be lying down; to settle

via Old Norse elfr

Step	Language	Word	Meaning
1	Old Norse	elfr	river
2	Proto-Germanic	albī	river
3	Latin	Albis	—
4	Latin	Albeus	—

Every word from Proto-Indo-European ḱey- →