Where does “skull” come from?

Skull comes from Middle English sculle, from Old Norse skalli, from Proto-Germanic skwal-, from Proto-Germanic skul-.

skull (English): The main bones of the head considered as a unit;...

Definitions

Step	Language	Word	Meaning
1	Middle English	sculle	a type of oar
2	Old Norse	skalli	a bald head; bald head, skull
3	Proto-Germanic	skaljō	shell; husk; rind; peel
4	Proto-Indo-European	(s)kelH-	to cut; to split, to separate
5	Proto-Indo-European	(s)kel-	to bend, crook; bent, crooked; leg, heel, knee,...

skull — Etymology, Origin & Word History | Etymology Explorer