Where does “cran” come from?

cran (Old French) comes from Medieval Latin cranium, from Ancient Greek κρανίον, from Ancient Greek κάρα, from Proto-Hellenic *kárahə.

Ancestry of “cran”, step by step

Step	Language	Word	Meaning
1	Medieval Latin	cranium	skull
2	Ancient Greek	κρανίον	skull; head
3	Ancient Greek	κάρα	head, face; the head or top of anything, as of a...
4	Proto-Hellenic	*kárahə	—

cran — Etymology, Origin & Word History | Etymology Explorer