primer coat vs primer

primer coat and primer both are nouns.

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

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

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

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

primer 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