Noun forms for the verb to vary are variation, variability, variable, and the gerund, varying.
Yes, it is a noun. It is a difference between nominal values, the noun form of the verb to vary.
Vary is the corresponding verb to the noun variety
The noun form for the adjective horrible is horribleness.
The noun form of the adjective obedient is obedience.
The noun form of the adjective 'prosperous' is prosperousness.A related noun form is prosperity.
The noun form is punisher
noun form of religious
Implication is the noun form of "imply."
The noun form for the adjective glaring is glaringness. Another noun form is glare.
The noun form for the adjective austere is austereness. Another noun form is austerity.
The noun form for the adjective acrimonious is acrimoniousness.A related noun form is acrimony.
noun = mud The noun form for the adjective muddy is muddiness.