Where does “mensurare” come from?

mensurare (Latin) comes from Latin mēnsūra, from Latin mētior, from Proto-Indo-European meh₁- — to measure.

Ancestry of “mensurare”, step by step

Step	Language	Word	Meaning
1	Latin	mēnsūra	—
2	Latin	mētior	—
3	Proto-Indo-European	meh₁-	to measure

mensurare — Etymology, Origin & Word History | Etymology Explorer