Where does “ούλο” come from?

ούλο (Greek) comes from Ancient Greek οὖλον, from Latin -rrhagia, from Ancient Greek -ραγία, from Ancient Greek ῥήγνυμι, from Proto-Indo-European wreh₁ǵ- — to break, tear.

ούλο (Greek): gingiva, gum

Definitions

gingiva, gum

Ancestry of “ούλο”, step by step

Step	Language	Word	Meaning
1	Ancient Greek	οὖλον	gum (flesh around the teeth)
2	Latin	-rrhagia	—
3	Ancient Greek	-ραγία	—
4	Ancient Greek	ῥήγνυμι	I break asunder, tear, rend, shatter; I break,...
5	Proto-Indo-European	wreh₁ǵ-	to break, tear

Every word from Proto-Indo-European wreh₁ǵ- →Every word from Ancient Greek ῥήγνυμι →Every word from Latin -rrhagia →