meeting vs social affair

meeting and social affair both are nouns.

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

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

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

meeting (noun)	social affair (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)