calling together vs assemblage

calling together and assemblage both are nouns.

Word	Noun	Adjective	Verb	Adverb
calling together	Yes	No	No	No
assemblage	Yes	No	No	No

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

Other hypernyms of calling together include assembly, gathering.

calling together (noun)	assemblage (noun)
the act of convoking	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