back matter vs end matter

back matter and end matter both are nouns.

Word	Noun	Adjective	Verb	Adverb
back matter	Yes	No	No	No
end matter	Yes	No	No	No

As nouns, back matter and end matter are synonyms defined as:

back matter and end matter: written matter following the main text of a book

back matter (noun)	end matter (noun)
written matter following the main text of a book	written matter following the main text of a book