merging vs concourse

merging and concourse both are nouns.

Word	Noun	Adjective	Verb	Adverb
merging	Yes	Yes	No	No
concourse	Yes	No	No	No

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

Other hyponyms of merging include confluence.

merging (noun)	concourse (noun)
a flowing together	a coming together of people
the act of joining together as one	a wide hallway in a building where people can walk
	a large gathering of people

merging (adjective)	concourse (adjective)
flowing together