rotundness vs rotundity

rotundness and rotundity both are nouns.

Word	Noun	Adjective	Verb	Adverb
rotundness	Yes	No	No	No
rotundity	Yes	No	No	No

As nouns, rotundness and rotundity are synonyms defined as:

Other synonyms of rotundness include globosity, globularness, sphericalness, sphericity.

rotundness (noun)	rotundity (noun)
the roundness of a 3-dimensional object	the roundness of a 3-dimensional object
	the fullness of a tone of voice