ending vs occurrence

ending and occurrence both are nouns.

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

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

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

ending (noun)	occurrence (noun)
the act of ending something	an event that happens
the end of a word (a suffix or inflectional ending or final morpheme)	an instance of something occurring
the last section of a communication
event whose occurrence ends something
the point in time at which something ends