invoke vs invocation

invoke is not a noun while invocation is a noun.

Word	Noun	Adjective	Verb	Adverb
invoke	No	No	Yes	No
invocation	Yes	No	No	No

invoke (noun)	invocation (noun)
	the act of appealing for help
	calling up a spirit or devil
	a prayer asking God's help as part of a religious service
	an incantation used in conjuring or summoning a devil

invoke (verb)	invocation (verb)
cite as an authority; resort to
request earnestly (something from somebody); ask for aid or protection
summon into action or bring into existence, often as if by magic