measuring vs mensuration

measuring and mensuration both are nouns.

Word	Noun	Adjective	Verb	Adverb
measuring	Yes	No	No	No
mensuration	Yes	No	No	No

As nouns, measuring and mensuration are synonyms defined as:

measuring and mensuration: the act or process of assigning numbers to phenomena according to a rule

Other synonyms of measuring include measure, measurement.

measuring (noun)	mensuration (noun)
the act or process of assigning numbers to phenomena according to a rule	the act or process of assigning numbers to phenomena according to a rule