revocation vs annulment

revocation and annulment both are nouns.

Word	Noun	Adjective	Verb	Adverb
revocation	Yes	No	No	No
annulment	Yes	No	No	No

As nouns, annulment is a hypernym of revocation; that is, annulment is a word with a broader meaning than revocation:

revocation: the act (by someone having the authority) of annulling something previously done
annulment: the act of abrogating; an official or legal cancellation

Other hypernyms of revocation include abrogation, repeal.

As nouns, revocation and annulment are synonyms defined as:

revocation (noun)	annulment (noun)
the act (by someone having the authority) of annulling something previously done	(law) a formal termination (of a relationship or a judicial proceeding etc)
the state of being cancelled or annulled	the act of abrogating; an official or legal cancellation
	the state of being cancelled or annulled