omission vs oversight

omission and oversight both are nouns.

Word	Noun	Adjective	Verb	Adverb
omission	Yes	No	No	No
oversight	Yes	No	No	No

As nouns, oversight is a hyponym of omission; that is, oversight is a word with a more specific, narrower meaning than omission:

omission: neglecting to do something; leaving out or passing over something
oversight: an unintentional omission resulting from failure to notice something

Other hyponyms of omission include inadvertence, pretermission, elision, exception, exclusion.

omission (noun)	oversight (noun)
a mistake resulting from neglect	a mistake resulting from inattention
neglecting to do something; leaving out or passing over something	management by overseeing the performance or operation of a person or group
any process whereby sounds or words are left out of spoken words or phrases	an unintentional omission resulting from failure to notice something
something that has been omitted