The Collaborative International Dictionary of English v.0.48:

Seal \Seal\, n. [OE. seel, OF. seel, F. sceau, fr. L. sigillum a
   little figure or image, a seal, dim. of signum a mark, sign,
   figure, or image. See Sign, n., and cf. Sigil.]
   1. An engraved or inscribed stamp, used for marking an
      impression in wax or other soft substance, to be attached
      to a document, or otherwise used by way of authentication
      or security.
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   2. Wax, wafer, or other tenacious substance, set to an
      instrument, and impressed or stamped with a seal; as, to
      give a deed under hand and seal.
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            Till thou canst rail the seal from off my bond
            Thou but offend'st thy lungs to speak so loud.
                                                  --Shak.
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   3. That which seals or fastens; esp., the wax or wafer placed
      on a letter or other closed paper, etc., to fasten it.
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   4. That which confirms, ratifies, or makes stable; that which
      authenticates; that which secures; assurance. "Under the
      seal of silence." --Milton.
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            Like a red seal is the setting sun
            On the good and the evil men have done.
                                                  --Longfellow.
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   5. An arrangement for preventing the entrance or return of
      gas or air into a pipe, by which the open end of the pipe
      dips beneath the surface of water or other liquid, or a
      deep bend or sag in the pipe is filled with the liquid; a
      draintrap.
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   Great seal. See under Great.

   Privy seal. See under Privy, a.

   Seal lock, a lock in which the keyhole is covered by a seal
      in such a way that the lock can not be opened without
      rupturing the seal.

   Seal manual. See under Manual, a.

   Seal ring, a ring having a seal engraved on it, or
      ornamented with a device resembling a seal; a signet ring.
      --Shak.
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The Collaborative International Dictionary of English v.0.48:

Privy \Priv"y\, a. [F. priv['e], fr. L. privatus. See
   Private.]
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   1. Of or pertaining to some person exclusively; assigned to
      private uses; not public; private; as, the privy purse. "
      Privee knights and squires." --Chaucer.
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   2. Secret; clandestine. " A privee thief." --Chaucer.
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   3. Appropriated to retirement; private; not open to the
      public. " Privy chambers." --Ezek. xxi. 14.
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   4. Admitted to knowledge of a secret transaction; secretly
      cognizant; privately knowing.
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            His wife also being privy to it.      --Acts v. 2.
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            Myself am one made privy to the plot. --Shak.
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   Privy chamber, a private apartment in a royal residence.
      [Eng.]

   Privy council (Eng. Law), the principal council of the
      sovereign, composed of the cabinet ministers and other
      persons chosen by the king or queen. --Burrill.

   Privy councilor, a member of the privy council.

   Privy purse, moneys set apart for the personal use of the
      monarch; also, the title of the person having charge of
      these moneys. [Eng.] --Macaulay.

   Privy seal or Privy signet, the seal which the king uses
      in grants, etc., which are to pass the great seal, or
      which he uses in matters of subordinate consequence which
      do not require the great seal; also, elliptically, the
      principal secretary of state, or person intrusted with the
      privy seal. [Eng.]

   Privy verdict, a verdict given privily to the judge out of
      court; -- now disused. --Burrill.
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Bouvier's Law Dictionary, Revised 6th Ed (1856):

PRIVY SEAL, Eng. law. A seal which the king uses to such grants or things as
pass the great seal. 2 Inst. 554.