Where does “pap” come from?

pap (Middle Welsh) comes from Proto-Brythonic *pab, from Vulgar Latin papa, from Latin papa, from Ancient Greek παπᾶς, from Old Norse súla, from Proto-Germanic sūliz, from Proto-Indo-European ḱsewl-, from Proto-Indo-European ḱsew- — to scrape, shave, sharpen.

Ancestry of “pap”, step by step

Step	Language	Word	Meaning
1	Proto-Brythonic	*pab	—
2	Vulgar Latin	papa	—
3	Latin	papa	an infant's cry for food; father; bishop
4	Ancient Greek	παπᾶς	priest
5	Old Norse	súla	pillar, column
6	Proto-Germanic	sūliz	beam, post; column, pillar
7	Proto-Indo-European	ḱsewl-	—
8	Proto-Indo-European	ḱsew-	to scrape, shave, sharpen

Words derived from “pap”

pab
pabydd
pabaeth
pabyddiaeth
pabyddol

Every word from Proto-Indo-European ḱsew- →Every word from Proto-Indo-European ḱsewl- →Every word from Proto-Germanic sūliz →