meeting vs convention

meeting and convention both are nouns.

Word	Noun	Adjective	Verb	Adverb
meeting	Yes	No	No	No
convention	Yes	No	No	No

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

meeting (noun)	convention (noun)
the social act of assembling for some common purpose	the act of convening
the act of joining together as one	orthodoxy as a consequence of being conventional
a casual or unexpected convergence	something regarded as a normative example
a formally arranged gathering	(diplomacy) an international agreement
a small informal social gathering	a large formal assembly
a place where things merge or flow together (especially rivers)