Source : Webster's Revised Unabridged Dictionary (1913)

   10. (Mus.)
       (a) Produced by natural organs, as those of the human
           throat, in distinction from instrumental music.
       (b) Of or pertaining to a key which has neither a flat
           nor a sharp for its signature, as the key of C major.
       (c) Applied to an air or modulation of harmony which
           moves by easy and smooth transitions, digressing but
           little from the original key. --Moore (Encyc. of
           Music).

   {Natural day}, the space of twenty-four hours. --Chaucer.

   {Natural fats}, {Natural gas}, etc. See under {Fat}, {Gas}.
      etc.

   {Natural Harmony} (Mus.), the harmony of the triad or common
      chord.

   {Natural history}, in its broadest sense, a history or
      description of nature as a whole, incuding the sciences of
      {botany}, {zo["o]logy}, {geology}, {mineralogy},
      {paleontology}, {chemistry}, and {physics}. In recent
      usage the term is often restricted to the sciences of
      botany and zo["o]logy collectively, and sometimes to the
      science of zoology alone.

   {Natural law}, that instinctive sense of justice and of right
      and wrong, which is native in mankind, as distinguished
      from specifically revealed divine law, and formulated
      human law.

   {Natural modulation} (Mus.), transition from one key to its
      relative keys.

   {Natural order}. (Nat. Hist.) See under {order}.

   {Natural person}. (Law) See under {person}, n.

   {Natural philosophy}, originally, the study of nature in
      general; in modern usage, that branch of physical science,
      commonly called {physics}, which treats of the phenomena
      and laws of matter and considers those effects only which
      are unaccompanied by any change of a chemical nature; --
      contrasted with mental and moral philosophy.

   {Natural scale} (Mus.), a scale which is written without
      flats or sharps. Model would be a preferable term, as less
      likely to mislead, the so-called artificial scales (scales
      represented by the use of flats and sharps) being equally
      natural with the so-called natural scale

   {Natural science}, natural history, in its broadest sense; --
      used especially in contradistinction to mental or moral
      science.

   {Natural selection} (Biol.), a supposed operation of natural
      laws analogous, in its operation and results, to designed
      selection in breeding plants and animals, and resulting in
      the survival of the fittest. The theory of natural
      selection supposes that this has been brought about mainly
      by gradual changes of environment which have led to
      corresponding changes of structure, and that those forms
      which have become so modified as to be best adapted to the
      changed environment have tended to survive and leave
      similarly adapted descendants, while those less perfectly
      adapted have tended to die out though lack of fitness for
      the environment, thus resulting in the survival of the
      fittest. See {Darwinism}.

   {Natural system} (Bot. & Zo["o]l.), a classification based
      upon real affinities, as shown in the structure of all
      parts of the organisms, and by their embryology.

            It should be borne in mind that the natural system
            of botany is natural only in the constitution of its
            genera, tribes, orders, etc., and in its grand
            divisions.                            --Gray.
      

   {Natural theology}, or {Natural religion}, that part of
      theological science which treats of those evidences of the
      existence and attributes of the Supreme Being which are
      exhibited in nature; -- distinguished from revealed
      religion. See Quotation under {Natural}, a., 3.

   {Natural vowel}, the vowel sound heard in urn, furl, sir,
      her, etc.; -- so called as being uttered in the easiest
      open position of the mouth organs. See {Neutral vowel},
      under {Neutral} and Guide to Pronunciation, [sect] 17.

   Syn: See {Native}.



   9. A body of persons having some common honorary distinction
      or rule of obligation; esp., a body of religious persons
      or aggregate of convents living under a common rule; as,
      the Order of the Bath; the Franciscan order.

            Find a barefoot brother out, One of our order, to
            associate me.                         --Shak.

            The venerable order of the Knights Templars. --Sir
                                                  W. Scott.

   10. An ecclesiastical grade or rank, as of deacon, priest, or
       bishop; the office of the Christian ministry; -- often
       used in the plural; as, to take orders, or to take holy
       orders, that is, to enter some grade of the ministry.

   11. (Arch.) The disposition of a column and its component
       parts, and of the entablature resting upon it, in
       classical architecture; hence (as the column and
       entablature are the characteristic features of classical
       architecture) a style or manner of architectural
       designing.

   Note: The Greeks used three different orders, easy to
         distinguish, Doric, Ionic, and Corinthian. The Romans
         added the Tuscan, and changed the Doric so that it is
         hardly recognizable, and also used a modified
         Corinthian called Composite. The Renaissance writers on
         architecture recognized five orders as orthodox or
         classical, -- Doric (the Roman sort), Ionic, Tuscan,
         Corinthian, and Composite. See Illust. of {Capital}.

   12. (Nat. Hist.) An assemblage of genera having certain
       important characters in common; as, the Carnivora and
       Insectivora are orders of Mammalia.

   Note: The Linn[ae]an artificial orders of plants rested
         mainly on identity in the numer of pistils, or
         agreement in some one character. Natural orders are
         groups of genera agreeing in the fundamental plan of
         their flowers and fruit. A natural order is usually (in
         botany) equivalent to a family, and may include several
         tribes.

   13. (Rhet.) The placing of words and members in a sentence in
       such a manner as to contribute to force and beauty or
       clearness of expression.

   14. (Math.) Rank; degree; thus, the order of a curve or
       surface is the same as the degree of its equation.

   {Artificial order} or {system}. See {Artificial
      classification}, under {Artificial}, and Note to def. 12
      above.

   {Close order} (Mil.), the arrangement of the ranks with a
      distance of about half a pace between them; with a
      distance of about three yards the ranks are in {open
      order}.

   {The four Orders}, {The Orders four}, the four orders of
      mendicant friars. See {Friar}. --Chaucer.

   {General orders} (Mil.), orders issued which concern the
      whole command, or the troops generally, in distinction
      from special orders.

   {Holy orders}.
       (a) (Eccl.) The different grades of the Christian
           ministry; ordination to the ministry. See def. 10
           above.
       (b) (R. C. Ch.) A sacrament for the purpose of conferring
           a special grace on those ordained.

   {In order to}, for the purpose of; to the end; as means to.

            The best knowledge is that which is of greatest use
            in order to our eternal happiness.    --Tillotson.

   {Minor orders} (R. C. Ch.), orders beneath the diaconate in
      sacramental dignity, as acolyte, exorcist, reader,
      doorkeeper.

   {Money order}. See under {Money}.

   {Natural order}. (Bot.) See def. 12, Note.

   {Order book}.
       (a) A merchant's book in which orders are entered.
       (b) (Mil.) A book kept at headquarters, in which all
           orders are recorded for the information of officers
           and men.
       (c) A book in the House of Commons in which proposed
           orders must be entered. [Eng.]

   {Order in Council}, a royal order issued with and by the
      advice of the Privy Council. [Great Britain]

   {Order of battle} (Mil.), the particular disposition given to
      the troops of an army on the field of battle.

   {Order of the day}, in legislative bodies, the special
      business appointed for a specified day.

   {Order of a differential equation} (Math.), the greatest
      index of differentiation in the equation.

   {Sailing orders} (Naut.), the final instructions given to the
      commander of a ship of war before a cruise.

   {Sealed orders}, orders sealed, and not to be opened until a
      certain time, or arrival at a certain place, as after a
      ship is at sea.

   {Standing order}.
       (a) A continuing regulation for the conduct of
           parliamentary business.
       (b) (Mil.) An order not subject to change by an officer
           temporarily in command.

   {To give order}, to give command or directions. --Shak.

   {To take order for}, to take charge of; to make arrangements
      concerning.

            Whiles I take order for mine own affairs. --Shak.

   Syn: Arrangement; management. See {Direction}.

Source : WordNet®

natural order
     n : the physical universe considered as an orderly system
         subject to natural (not human or supernatural) laws