The Collaborative International Dictionary of English v.0.48:

Codex \Co"dex\ (k[=o]"d[e^]ks), n.; pl. Codices. [L. See
   Code.]
   1. A book, especially an early form of book with pages
      stitched together, contrasting with the earlier scrolls; a
      manuscript; as, a DaVinci codex.
      [1913 Webster]

   2. A collection or digest of laws; a code(senses 2 or 4).
      [archaic] --Burrill.
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   3. An ancient manuscript of the Sacred Scriptures, or any
      part of them, particularly the New Testament.
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   4. A collection of canons. --Shipley.
      [1913 Webster]