intercession vs prayer

intercession and prayer both are nouns.

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

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

Other hypernyms of intercession include orison, petition.

intercession (noun)	prayer (noun)
the act of intervening (as to mediate a dispute, etc.)	the act of communicating with a deity (especially as a petition or in adoration or contrition or thanksgiving)
a prayer to God on behalf of another person	earnest or urgent request
	a fixed text used in praying
	reverent petition to a deity
	someone who prays to God