school text vs primer

school text and primer both are nouns.

Word	Noun	Adjective	Verb	Adverb
school text	Yes	No	No	No
primer	Yes	No	No	No

As nouns, primer is a hyponym of school text; that is, primer is a word with a more specific, narrower meaning than school text:

Other hyponyms of school text include crammer, introduction, reader.

school text (noun)	primer (noun)
a book prepared for use in schools or colleges	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