holograph vs codex

holograph and codex both are nouns.

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

As nouns, codex is a hyponym of holograph; that is, codex is a word with a more specific, narrower meaning than holograph:

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

Other hyponyms of holograph include leaf-book, palimpsest, roll, scroll.

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