eventuality vs occurrence

eventuality and occurrence both are nouns.

Word	Noun	Adjective	Verb	Adverb
eventuality	Yes	No	No	No
occurrence	Yes	No	No	No

As nouns, occurrence is a hypernym of eventuality; that is, occurrence is a word with a broader meaning than eventuality:

Other hypernyms of eventuality include happening, natural event, occurrent.

eventuality (noun)	occurrence (noun)
a possible event or occurrence or result	an event that happens
	an instance of something occurring