Adjective
Of or pertaining to the first canon, or that which contains the authorized collection of the books of Scripture; -- opposed to deutero-canonical.
Source: Webster's dictionaryOther New Testament authors such as Paul also reference or quote period literature citation which was familiar to the audience but that was not included in the deuterocanonical or the protocanonical Old Testament books. Source: Internet
Books found in both the Hebrew and the Greek are accepted by all denominations, and by Jews, these are the protocanonical books. Source: Internet
Moreover, the protocanonical part of Daniel following chapter 3 is commonly missing. Source: Internet