intermediation vs intercession

intermediation and intercession both are nouns.

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

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

intermediation: the act of intervening for the purpose of bringing about a settlement
intercession: the act of intervening (as to mediate a dispute, etc.)

Other hypernyms of intermediation include intervention.

intermediation (noun)	intercession (noun)
the act of intervening for the purpose of bringing about a settlement	the act of intervening (as to mediate a dispute, etc.)
	a prayer to God on behalf of another person