end matter vs back matter

end matter and back matter both are nouns.

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

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

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

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