fortuity vs natural event

fortuity and natural event both are nouns.

Word	Noun	Adjective	Verb	Adverb
fortuity	Yes	No	No	No
natural event	Yes	No	No	No

As nouns, natural event is a hypernym of fortuity; that is, natural event is a word with a broader meaning than fortuity:

fortuity: anything that happens suddenly or by chance without an apparent cause
natural event: an event that happens

Other hypernyms of fortuity include happening, occurrence, occurrent.

fortuity (noun)	natural event (noun)
anything that happens suddenly or by chance without an apparent cause	an event that happens