meeting vs social gathering

meeting and social gathering both are nouns.

Word	Noun	Adjective	Verb	Adverb
meeting	Yes	No	No	No
social gathering	Yes	No	No	No

As nouns, social gathering is a hypernym of meeting; that is, social gathering is a word with a broader meaning than meeting:

meeting: a small informal social gathering
social gathering: a formal or official social gathering or ceremony of people

Other hypernyms of meeting include affair, function, occasion, social affair, social function, social occasion.

meeting (noun)	social gathering (noun)
the social act of assembling for some common purpose	a formal or official social gathering or ceremony of people
the act of joining together as one
a casual or unexpected convergence
a formally arranged gathering
a small informal social gathering
a place where things merge or flow together (especially rivers)