The Collaborative International Dictionary of English v.0.48:

Compensation \Com`pen*sa"tion\, n. [L. compensatio a weighing, a
   balancing of accounts.]
   1. The act or principle of compensating. --Emerson.
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   2. That which constitutes, or is regarded as, an equivalent;
      that which makes good the lack or variation of something
      else; that which compensates for loss or privation;
      amends; remuneration; recompense.
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            The parliament which dissolved the monastic
            foundations . . . vouchsafed not a word toward
            securing the slightest compensation to the
            dispossessed owners.                  --Hallam.
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            No pecuniary compensation can possibly reward them.
                                                  --Burke.
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   3. (Law)
      (a) The extinction of debts of which two persons are
          reciprocally debtors by the credits of which they are
          reciprocally creditors; the payment of a debt by a
          credit of equal amount; a set-off. --Bouvier.
          --Wharton.
      (b) A recompense or reward for some loss or service.
      (c) An equivalent stipulated for in contracts for the sale
          of real estate, in which it is customary to provide
          that errors in description, etc., shall not avoid, but
          shall be the subject of compensation.
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   Compensation balance, or Compensated balance, a kind of
      balance wheel for a timepiece. The rim is usually made of
      two different metals having different expansibility under
      changes of temperature, so arranged as to counteract each
      other and preserve uniformity of movement.

   Compensation pendulum. See Pendulum.

   Syn: Recompense; reward; indemnification; consideration;
        requital; satisfaction; set-off.
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The Collaborative International Dictionary of English v.0.48:

Pendulum \Pen"du*lum\, n.; pl. Pendulums. [NL., fr. L.
   pendulus hanging, swinging. See Pendulous.]
   A body so suspended from a fixed point as to swing freely to
   and fro by the alternate action of gravity and momentum. It
   is used to regulate the movements of clockwork and other
   machinery.
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   Note: The time of oscillation of a pendulum is independent of
         the arc of vibration, provided this arc be small.
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   Ballistic pendulum. See under Ballistic.

   Compensation pendulum, a clock pendulum in which the effect
      of changes of temperature of the length of the rod is so
      counteracted, usually by the opposite expansion of
      differene metals, that the distance of the center of
      oscillation from the center of suspension remains
      invariable; as, the mercurial compensation pendulum, in
      which the expansion of the rod is compensated by the
      opposite expansion of mercury in a jar constituting the
      bob; the gridiron pendulum, in which compensation is
      effected by the opposite expansion of sets of rods of
      different metals.

   Compound pendulum, an ordinary pendulum; -- so called, as
      being made up of different parts, and contrasted with
      simple pendulum.

   Conical pendulum or Revolving pendulum, a weight
      connected by a rod with a fixed point; and revolving in a
      horizontal circle about the vertical from that point.

   Pendulum bob, the weight at the lower end of a pendulum.

   Pendulum level, a plumb level. See under Level.

   Pendulum wheel, the balance of a watch.

   Simple pendulum or Theoretical pendulum, an imaginary
      pendulum having no dimensions except length, and no weight
      except at the center of oscillation; in other words, a
      material point suspended by an ideal line.
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