incident vs occurrence

incident and occurrence both are nouns.

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

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

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

incident (noun)	occurrence (noun)
a single distinct event	an event that happens
a public disturbance	an instance of something occurring

incident (adjective)	occurrence (adjective)
(sometimes followed by `to') minor or casual or subordinate in significance or nature or occurring as a chance concomitant or consequence
falling or striking of light rays on something