1. [n]  a collection of books accepted as holy scripture especially the books of the Bible recognized by any Christian church as genuine and inspired
2. [n]  a complete list of saints that have been recognized by the Roman Catholic Church
3. [n]  a rule or especially body of rules or principles generally established as valid and fundamental in a field or art or philosophy; "the neoclassical canon"; "canons of polite society"
4. [n]  a contrapuntal piece of music in which a melody in one part is imitated exactly in other parts
5. [n]  (North America) a ravine formed by a river in an area with little rainfall
6. [n]  a priest who is a member of a cathedral chapter

1. \Can"on\, n. [OE. canon, canoun, AS. canon rule (cf. F.
   canon, LL. canon, and, for sense 7, F. chanoine, LL.
   canonicus), fr. L. canon a measuring line, rule, model, fr.
   Gr. ? rule, rod, fr. ?, ?, red. See {Cane}, and cf.
   {Canonical}.]
   1. A law or rule.
   
            Or that the Everlasting had not fixed His canon
            'gainst self-slaughter.               --Shak.
   
   2. (Eccl.) A law, or rule of doctrine or discipline, enacted
      by a council and confirmed by the pope or the sovereign; a
      decision, regulation, code, or constitution made by
      ecclesiastical authority.
   
            Various canons which were made in councils held in
            the second centry.                    --Hock.
   
   3. The collection of books received as genuine Holy
      Scriptures, called the {sacred canon}, or general rule of
      moral and religious duty, given by inspiration; the Bible;
      also, any one of the canonical Scriptures. See {Canonical
      books}, under {Canonical}, a.
   
   4. In monasteries, a book containing the rules of a religious
      order.
   
   5. A catalogue of saints acknowledged and canonized in the
      Roman Catholic Church.
   
   6. A member of a cathedral chapter; a person who possesses a
      prebend in a cathedral or collegiate church.
   
   7. (Mus.) A musical composition in which the voices begin one
      after another, at regular intervals, successively taking
      up the same subject. It either winds up with a coda
      (tailpiece), or, as each voice finishes, commences anew,
      thus forming a perpetual fugue or round. It is the
      strictest form of imitation. See {Imitation}.
   
   8. (Print.) The largest size of type having a specific name;
      -- so called from having been used for printing the canons
      of the church.
   
   9. The part of a bell by which it is suspended; -- called
      also {ear} and {shank}.
   
   Note: [See Illust. of {Bell}.] --Knight.
   
   10. (Billiards) See {Carom}.
   
   {Apostolical canons}. See under {Apostolical}.
   
   {Augustinian canons}, {Black canons}. See under
      {Augustinian}.
   
   {Canon capitular}, {Canon residentiary}, a resident member of
      a cathedral chapter (during a part or the whole of the
      year).
   
   {Canon law}. See under {Law}.
   
   {Canon of the Mass} (R. C. Ch.), that part of the mass,
      following the Sanctus, which never changes.
   
   {Honorary canon}, a canon who neither lived in a monastery,
      nor kept the canonical hours.
   
   {Minor canon} (Ch. of Eng.), one who has been admitted to a
      chapter, but has not yet received a prebend.
   
   {Regular canon} (R. C. Ch.), one who lived in a conventual
      community and follower the rule of St. Austin; a Black
      canon.
   
   {Secular canon} (R. C. Ch.), one who did not live in a
      monastery, but kept the hours.
   
   

2. \Ca*[~n]on"\, n. [Sp., a tube or hollow, fr. ca[~n]a reed,
   fr. L. canna. See {Cane}.]
   A deep gorge, ravine, or gulch, between high and steep banks,
   worn by water courses. [Mexico & Western U. S.]
   
   

This word is derived from a Hebrew and Greek word denoting a reed or cane. Hence it means something straight, or something to keep straight; and hence also a rule, or something ruled or measured. It came to be applied to the Scriptures, to denote that they contained the authoritative rule of faith and practice, the standard of doctrine and duty. A book is said to be of canonical authority when it has a right to take a place with the other books which contain a revelation of the Divine will. Such a right does not arise from any ecclesiastical authority, but from the evidence of the inspired authorship of the book. The canonical (i.e., the inspired) books of the Old and New Testaments, are a complete rule, and the only rule, of faith and practice. They contain the whole supernatural revelation of God to men. The New Testament Canon was formed gradually under divine guidance. The different books as they were written came into the possession of the Christian associations which began to be formed soon after the day of Pentecost; and thus slowly the canon increased till all the books were gathered together into one collection containing the whole of the twenty-seven New Testament inspired books. Historical evidence shows that from about the middle of the second century this New Testament collection was substantially such as we now possess. Each book contained in it is proved to have, on its own ground, a right to its place; and thus the whole is of divine authority.

The Old Testament Canon is witnessed to by the New Testament writers. Their evidence is conclusive. The quotations in the New from the Old are very numerous, and the references are much more numerous. These quotations and references by our Lord and the apostles most clearly imply the existence at that time of a well-known and publicly acknowledged collection of Hebrew writings under the designation of "The Scriptures;" "The Law and the Prophets and the Psalms;" "Moses and the Prophets," etc. The appeals to these books, moreover, show that they were regarded as of divine authority, finally deciding all questions of which they treat; and that the whole collection so recognized consisted only of the thirty-nine books which we now posses. Thus they endorse as genuine and authentic the canon of the Jewish Scriptures. The Septuagint Version (q.v.) also contained every book we now have in the Old Testament Scriptures. As to the time at which the Old Testament canon was closed, there are many considerations which point to that of Ezra and Nehemiah, immediately after the return from Babylonian exile. (See BIBLE ¯T0000580, EZRA, QUOTATIONS.)