codex vs holograph

codex and holograph both are nouns.

Word	Noun	Adjective	Verb	Adverb
codex	Yes	No	No	No
holograph	Yes	No	No	No

As nouns, holograph is a hypernym of codex; that is, holograph is a word with a broader meaning than codex:

codex: an unbound manuscript of some ancient classic (as distinguished from a scroll)
holograph: handwritten book or document

Other hypernyms of codex include manuscript.

codex (noun)	holograph (noun)
an unbound manuscript of some ancient classic (as distinguished from a scroll)	the intermediate photograph (or photographic record) that contains information for reproducing a three-dimensional image by holography
an official list of chemicals or medicines etc.	handwritten book or document