资料来源 : Webster's Revised Unabridged Dictionary (1913)

   {Law of Charles} (Physics), the law that the volume of a
      given mass of gas increases or decreases, by a definite
      fraction of its value for a given rise or fall of
      temperature; -- sometimes less correctly styled {Gay
      Lussac's law}, or {Dalton's law}.

   {Law of nations}. See {International law}, under
      {International}.

   {Law of nature}.
       (a) A broad generalization expressive of the constant
           action, or effect, of natural conditions; as, death
           is a law of nature; self-defense is a law of nature.
           See {Law}, 4.
       (b) A term denoting the standard, or system, of morality
           deducible from a study of the nature and natural
           relations of human beings independent of supernatural
           revelation or of municipal and social usages.

   {Law of the land}, due process of law; the general law of the
      land.

   {Laws of honor}. See under {Honor}.

   {Laws of motion} (Physics), three laws defined by Sir Isaac
      Newton: (1) Every body perseveres in its state of rest or
      of moving uniformly in a straight line, except so far as
      it is made to change that state by external force. (2)
      Change of motion is proportional to the impressed force,
      and takes place in the direction in which the force is
      impressed. (3) Reaction is always equal and opposite to
      action, that is to say, the actions of two bodies upon
      each other are always equal and in opposite directions.

   {Marine law}, or {Maritime law}, the law of the sea; a branch
      of the law merchant relating to the affairs of the sea,
      such as seamen, ships, shipping, navigation, and the like.
      --Bouvier.

   {Mariotte's law}. See {Boyle's law} (above).

   {Martial law}.See under {Martial}.

   {Military law}, a branch of the general municipal law,
      consisting of rules ordained for the government of the
      military force of a state in peace and war, and
      administered in courts martial. --Kent. Warren's
      Blackstone.

   {Moral law},the law of duty as regards what is right and
      wrong in the sight of God; specifically, the ten
      commandments given by Moses. See {Law}, 2.

   {Mosaic}, or {Ceremonial}, {law}. (Script.) See {Law}, 3.

   {Municipal}, or {Positive}, {law}, a rule prescribed by the
      supreme power of a state, declaring some right, enforcing
      some duty, or prohibiting some act; -- distinguished from
      international and constitutional law. See {Law}, 1.

   {Periodic law}. (Chem.) See under {Periodic}.

   {Roman law}, the system of principles and laws found in the
      codes and treatises of the lawmakers and jurists of
      ancient Rome, and incorporated more or less into the laws
      of the several European countries and colonies founded by
      them. See {Civil law} (above).

   {Statute law}, the law as stated in statutes or positive
      enactments of the legislative body.

   {Sumptuary law}. See under {Sumptuary}.

   {To go to law}, to seek a settlement of any matter by
      bringing it before the courts of law; to sue or prosecute
      some one.

   {To} {take, or have}, {the law of}, to bring the law to bear
      upon; as, to take the law of one's neighbor. --Addison.

   {Wager of law}. See under {Wager}.

   Syn: Justice; equity.

   Usage: {Law}, {Statute}, {Common law}, {Regulation}, {Edict},
          {Decree}. Law is generic, and, when used with
          reference to, or in connection with, the other words
          here considered, denotes whatever is commanded by one
          who has a right to require obedience. A statute is a
          particular law drawn out in form, and distinctly
          enacted and proclaimed. Common law is a rule of action
          founded on long usage and the decisions of courts of
          justice. A regulation is a limited and often,
          temporary law, intended to secure some particular end
          or object. An edict is a command or law issued by a
          sovereign, and is peculiar to a despotic government. A
          decree is a permanent order either of a court or of
          the executive government. See {Justice}.

Periodic \Pe`ri*od"ic\, Periodical \Pe`ri*od"ic*al\, a. [L.
   periodicus, Gr. ?: cf. F. p['e]riodique.]
   1. Of or pertaining to a period or periods, or to division by
      periods.

            The periodicaltimes of all the satellites. --Sir J.
                                                  Herschel.

   2. Performed in a period, or regular revolution; proceeding
      in a series of successive circuits; as, the periodical
      motion of the planets round the sun.

   3. Happening, by revolution, at a stated time; returning
      regularly, after a certain period of time; acting,
      happening, or appearing, at fixed intervals; recurring;
      as, periodical epidemics.

            The periodic return of a plant's flowering.
                                                  --Henslow.

            To influence opinion through the periodical press.
                                                  --Courthope.

   4. (Rhet.) Of or pertaining to a period; constituting a
      complete sentence.

   {Periodic comet} (Astron.), a comet that moves about the sun
      in an elliptic orbit; a comet that has been seen at two of
      its approaches to the sun.

   {Periodic function} (Math.), a function whose values recur at
      fixed intervals as the variable uniformly increases. The
      trigonomertic functions, as sin x, tan x, etc., are
      periodic functions. Exponential functions are also
      periodic, having an imaginary period, and the elliptic
      functions have not only a real but an imaginary period,
      and are hence called doubly periodic.

   {Periodic law} (Chem.), the generalization that the
      properties of the chemical elements are periodic functions
      of their atomic wieghts. ``In other words, if the elements
      are grouped in the order of their atomic weights, it will
      be found that nearly the same properties recur
      periodically throughout the entire series.'' The following
      tabular arrangement of the atomic weights shows the
      regular recurrence of groups (under I., II., III., IV.,
      etc.), each consisting of members of the same natural
      family. The gaps in the table indicate the probable
      existence of unknown elements.

资料来源 : WordNet®

periodic law
     n : (chemistry) the principle that chemical properties of the
         elements are periodic functions of their atomic numbers
         [syn: {Mendeleev's law}]