appearance vs occurrence

appearance and occurrence both are nouns.

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

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

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

appearance (noun)	occurrence (noun)
the act of appearing in public view	an event that happens
formal attendance (in court or at a hearing) of a party in an action	an instance of something occurring
pretending that something is the case in order to make a good impression
outward or visible aspect of a person or thing
a mental representation
the event of coming into sight