concurrence vs concur

concurrence is a noun but concur is not a noun.

Word	Noun	Adjective	Verb	Adverb
concurrence	Yes	No	No	No
concur	No	No	Yes	No

concurrence (noun)	concur (noun)
acting together, as agents or circumstances or events
the temporal property of two things happening at the same time
agreement of results or opinions
a state of cooperation

concurrence (verb)	concur (verb)
	happen simultaneously
	be in accord; be in agreement