congregating vs assemblage

congregating and assemblage both are nouns.

Word	Noun	Adjective	Verb	Adverb
congregating	Yes	No	No	No
assemblage	Yes	No	No	No

As nouns, assemblage is a hypernym of congregating; that is, assemblage is a word with a broader meaning than congregating:

Other hypernyms of congregating include assembly, gathering.

congregating (noun)	assemblage (noun)
the act of congregating	the social act of assembling
	a system of components assembled together for a particular purpose
	a group of persons together in one place
	several things grouped together or considered as a whole