coating vs finish coat

coating and finish coat both are nouns.

Word	Noun	Adjective	Verb	Adverb
coating	Yes	No	No	No
finish coat	Yes	No	No	No

As nouns, finish coat is a hyponym of coating; that is, finish coat is a word with a more specific, narrower meaning than coating:

coating (noun)	finish coat (noun)
the work of applying something	the final coating of (e.g., paint, plaster, varnish, etc.)
a thin layer covering something
a heavy fabric suitable for coats
a decorative texture or appearance of a surface (or the substance that gives it that appearance)