Where does “vert” come from?

vert (Old Occitan) comes from Vulgar Latin virdis, from Latin viridis, from Latin vireō, from Latin -idae.

Ancestry of “vert”, step by step

Step	Language	Word	Meaning
1	Vulgar Latin	virdis	—
2	Latin	viridis	green; young, fresh, lively, youthful
3	Latin	vireō	—
4	Latin	-idae	—

vert — Etymology, Origin & Word History | Etymology Explorer