variance vs vary

variance is a noun but vary is not a noun.

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

variance (noun)	vary (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

variance (verb)	vary (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