Canonical letters

canonic \ca*non"ic\ (k[.a]*n[o^]n"[i^]k), canonical
\ca*non"ic*al\ (k[.a]*n[o^]n"[i^]*kal), a. [L. canonicus, LL.
   canonicalis, fr. L. canon: cf. F. canonique. See {canon}.]
   Of or pertaining to a canon; established by, or according to,
   a canon or canons. "The oath of canonical obedience."
   --Hallam.
   [1913 Webster]

   2. Appearing in a Biblical canon; as, a canonical book of the
      Christian New Testament.
      [PJC]

   3. Accepted as authoritative; recognized.
      [PJC]

   4. (Math.) In its standard form, usually also the simplest
      form; -- of an equation or coordinate.
      [PJC]

   5. (Linguistics) Reduced to the simplest and most significant
      form possible without loss of generality; as, a canonical
      syllable pattern. Opposite of {nonstandard}.

   Syn: standard. [WordNet 1.5]

   6. Pertaining to or resembling a musical canon.
      [PJC]

   {Canonical books}, or {Canonical Scriptures}, those books
      which are declared by the canons of the church to be of
      divine inspiration; -- called collectively {the canon}.
      The Roman Catholic Church holds as canonical several books
      which Protestants reject as apocryphal.

   {Canonical epistles}, an appellation given to the epistles
      called also general or catholic. See {Catholic epistles},
      under {Canholic}.

   {Canonical form} (Math.), the simples or most symmetrical
      form to which all functions of the same class can be
      reduced without lose of generality.

   {Canonical hours}, certain stated times of the day, fixed by
      ecclesiastical laws, and appropriated to the offices of
      prayer and devotion; also, certain portions of the
      Breviary, to be used at stated hours of the day. In
      England, this name is also given to the hours from 8 a. m.
      to 3 p. m. (formerly 8 a. m. to 12 m.) before and after
      which marriage can not be legally performed in any parish
      church.

   {Canonical letters}, letters of several kinds, formerly given
      by a bishop to traveling clergymen or laymen, to show that
      they were entitled to receive the communion, and to
      distinguish them from heretics.

   {Canonical life}, the method or rule of living prescribed by
      the ancient clergy who lived in community; a course of
      living prescribed for the clergy, less rigid than the
      monastic, and more restrained that the secular.

   {Canonical obedience}, submission to the canons of a church,
      especially the submission of the inferior clergy to their
      bishops, and of other religious orders to their superiors.
      

   {Canonical punishments}, such as the church may inflict, as
      excommunication, degradation, penance, etc.

   {Canonical sins} (Anc. Church.), those for which capital
      punishment or public penance decreed by the canon was
      inflicted, as idolatry, murder, adultery, heresy.
      [1913 Webster]