school text vs textbook

school text and textbook both are nouns.

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

As nouns, school text and textbook are synonyms defined as:

school text and textbook: a book prepared for use in schools or colleges

Other synonyms of school text include schoolbook, text, text edition.

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

school text (adjective)	textbook (adjective)
	according to or characteristic of a casebook or textbook; typical