Where does “facula” come from?

facula (Latin) comes from Latin fax, from Proto-Indo-European ǵʷʰeh₂k- — to shine.

facula (Latin): small torch

Definitions

Step	Language	Word	Meaning
1	Latin	fax	torch, firebrand; fireball, comet; cause of ruin,...
2	Proto-Indo-European	ǵʷʰeh₂k-	to shine

facula — Etymology, Origin & Word History | Etymology Explorer