periodic event vs natural event

periodic event and natural event both are nouns.

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

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

Other hypernyms of periodic event include happening, occurrence, occurrent.

periodic event (noun)	natural event (noun)
an event that recurs at intervals	an event that happens