Where does “horn” come from?

horn (Old Dutch) comes from Proto-Germanic hurną, from Proto-Indo-European ḱer-, from Proto-Indo-European kr̥-, from Proto-Indo-European ker- — army.

Ancestry of “horn”, step by step

Step	Language	Word	Meaning
1	Proto-Germanic	hurną	horn
2	Proto-Indo-European	ḱer-	to grow, to make grow, to nourish; to plait,...
3	Proto-Indo-European	kr̥-	to turn, to bend
4	Proto-Indo-European	ker-	army

horn — Etymology, Origin & Word History | Etymology Explorer