Compound \Com"pound\, a. [OE. compouned, p. p. of compounen. See
   Compound, v. t.]
   Composed of two or more elements, ingredients, parts;
   produced by the union of several ingredients, parts, or
   things; composite; as, a compound word.
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         Compound substances are made up of two or more simple
         substances.                              --I. Watts.
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   Compound addition, subtraction, multiplication,
   division (Arith.), the addition, subtraction, etc., of
      compound numbers.

   Compound crystal (Crystallog.), a twin crystal, or one
      seeming to be made up of two or more crystals combined
      according to regular laws of composition.

   Compound engine (Mech.), a form of steam engine in which
      the steam that has been used in a high-pressure cylinder
      is made to do further service in a larger low-pressure
      cylinder, sometimes in several larger cylinders,
      successively.

   Compound ether. (Chem.) See under Ether.

   Compound flower (Bot.), a flower head resembling a single
      flower, but really composed of several florets inclosed in
      a common calyxlike involucre, as the sunflower or
      dandelion.

   Compound fraction. (Math.) See Fraction.

   Compound fracture. See Fracture.

   Compound householder, a householder who compounds or
      arranges with his landlord that his rates shall be
      included in his rents. [Eng.]

   Compound interest. See Interest.

   Compound larceny. (Law) See Larceny.

   Compound leaf (Bot.), a leaf having two or more separate
      blades or leaflets on a common leafstalk.

   Compound microscope. See Microscope.

   Compound motion. See Motion.

   Compound number (Math.), one constructed according to a
      varying scale of denomination; as, 3 cwt., 1 qr., 5 lb.;
      -- called also denominate number.

   Compound pier (Arch.), a clustered column.

   Compound quantity (Alg.), a quantity composed of two or
      more simple quantities or terms, connected by the sign +
      (plus) or - (minus). Thus, a + b - c, and bb - b, are
      compound quantities.

   Compound radical. (Chem.) See Radical.

   Compound ratio (Math.), the product of two or more ratios;
      thus ab:cd is a ratio compounded of the simple ratios a:c
      and b:d.

   Compound rest (Mech.), the tool carriage of an engine
      lathe.

   Compound screw (Mech.), a screw having on the same axis two
      or more screws with different pitch (a differential
      screw), or running in different directions (a right and
      left screw).

   Compound time (Mus.), that in which two or more simple
      measures are combined in one; as, 6-8 time is the joining
      of two measures of 3-8 time.

   Compound word, a word composed of two or more words;
      specifically, two or more words joined together by a
      hyphen.
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Ether \E"ther\ ([=e]"th[~e]r), n. [L. aether, Gr. a'iqh`r, fr.
   a'i`qein to light up, kindle, burn, blaze; akin to Skr. idh,
   indh, and prob. to E. idle: cf. F. ['e]ther.] [Written also
   [ae]ther.]
   1. (Physics) A medium of great elasticity and extreme
      tenuity, once supposed to pervade all space, the interior
      of solid bodies not excepted, and to be the medium of
      transmission of light and heat; hence often called
      luminiferous ether. It is no longer believed that such a
      medium is required for the transmission of electromagnetic
      waves; the modern use of the term is mostly a figurative
      term for empty space, or for literary effect, and not
      intended to imply the actual existence of a physical
      medium. However. modern cosmological theories based on
      quantum field theory do not rule out the possibility that
      the inherent energy of the vacuum is greater than zero, in
      which case the concept of an ether pervading the vacuum
      may have more than metaphoric meaning.
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   2. Supposed matter above the air; the air itself.
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   3. (Chem.)
      (a) A light, volatile, mobile, inflammable liquid,
          (C2H5)2O, of a characteristic aromatic odor,
          obtained by the distillation of alcohol with sulphuric
          acid, and hence called also sulphuric ether. It is a
          powerful solvent of fats, resins, and pyroxylin, but
          finds its chief use as an an[ae]sthetic. Commonly
          called ethyl ether to distinguish it from other
          ethers, and also ethyl oxide.
      (b) Any similar compound in which an oxygen atom is bound
          to two different carbon atoms, each of which is part
          of an organic radical; as, amyl ether; valeric ether;
          methyl ethyl ether. The general formular for an ether
          is ROR', in which R and R' are organic radicals
          which may be of similar or different structure. If R
          and R' are different parts of the same organic
          radical, the structure forms a cyclic ether.
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   Complex ether, Mixed ether (Chem.), an ether in which the
      ether oxygen is attached to two radicals having different
      structures; as, ethyl methyl ether, C2H5.O.CH3.

   Compound ether (Chem.), an ethereal salt or a salt of some
      hydrocarbon as the base; an ester.

   Ether engine (Mach.), a condensing engine like a steam
      engine, but operated by the vapor of ether instead of by
      steam.
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