invocation vs prayer

invocation and prayer both are nouns.

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

As nouns, prayer is a hypernym of invocation; that is, prayer is a word with a broader meaning than invocation:

Other hypernyms of invocation include orison, petition.

invocation (noun)	prayer (noun)
the act of appealing for help	the act of communicating with a deity (especially as a petition or in adoration or contrition or thanksgiving)
calling up a spirit or devil	earnest or urgent request
a prayer asking God's help as part of a religious service	a fixed text used in praying
an incantation used in conjuring or summoning a devil	reverent petition to a deity
	someone who prays to God