vary vs variance

vary is not a noun while variance is a noun.

Word	Noun	Adjective	Verb	Adverb
vary	No	No	Yes	No
variance	Yes	No	No	No

vary (noun)	variance (noun)
	an activity that varies from a norm or standard
	an official dispensation to act contrary to a rule or regulation (typically a building regulation)
	a difference between conflicting facts or claims or opinions
	the quality of being subject to variation
	the second moment around the mean; the expected value of the square of the deviations of a random variable from its mean value
	discord that splits a group
	an event that departs from expectations

vary (verb)	variance (verb)
become different in some particular way, without permanently losing one's or its former characteristics or essence
make something more diverse and varied
be at variance with; be out of line with
be subject to change in accordance with a variable