repetition vs periodic event

repetition and periodic event both are nouns.

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

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

Other hypernyms of repetition include recurrent event.

repetition (noun)	periodic event (noun)
the act of doing or performing again	an event that recurs at intervals
the repeated use of the same word or word pattern as a rhetorical device
an event that repeats