rotundness vs sphericity

rotundness and sphericity both are nouns.

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

As nouns, rotundness and sphericity are synonyms defined as:

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

rotundness (noun)	sphericity (noun)
the roundness of a 3-dimensional object	the roundness of a 3-dimensional object