congress vs gathering

congress and gathering both are nouns.

Word	Noun	Adjective	Verb	Adverb
congress	Yes	No	No	No
gathering	Yes	No	No	No

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

Other hypernyms of congress include assemblage, assembly.

congress (noun)	gathering (noun)
the social act of assembling for some common purpose	the social act of assembling
a meeting of elected or appointed representatives	the act of gathering something
a national legislative assembly	sewing consisting of small folds or puckers made by pulling tight a thread in a line of stitching
	a group of persons together in one place