priming coat vs primer

priming coat and primer both are nouns.

Word	Noun	Adjective	Verb	Adverb
priming coat	Yes	No	No	No
primer	Yes	No	No	No

As nouns, priming coat and primer are synonyms defined as:

priming coat and primer: the first or preliminary coat of paint or size applied to a surface

Other synonyms of priming coat include flat coat, ground, primer coat, priming, undercoat.

priming coat (noun)	primer (noun)
the first or preliminary coat of paint or size applied to a surface	any igniter that is used to initiate the burning of a propellant
	the first or preliminary coat of paint or size applied to a surface
	an introductory textbook