leaf-book vs codex

leaf-book and codex both are nouns.

Word	Noun	Adjective	Verb	Adverb
leaf-book	Yes	No	No	No
codex	Yes	No	No	No

As nouns, leaf-book and codex are synonyms defined as:

leaf-book and codex: an unbound manuscript of some ancient classic (as distinguished from a scroll)

leaf-book (noun)	codex (noun)
an unbound manuscript of some ancient classic (as distinguished from a scroll)	an unbound manuscript of some ancient classic (as distinguished from a scroll)
	an official list of chemicals or medicines etc.