Source : Webster's Revised Unabridged Dictionary (1913)

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.

   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.

            Till thou canst rail the seal from off my bond Thou
            but offend;st thy lungs to speak so loud. --Shak.

   3. That which seals or fastens; esp., the wax or wafer placed
      on a letter or other closed paper, etc., to fasten it.

   4. That which confirms, ratifies, or makes stable; that which
      authenticates; that which secures; assurance. ``under the
      seal of silence.'' --Milton.

            Like a red seal is the setting sun On the good and
            the evil men have done.               --Lonfellow.

   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.

   {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.

Source : WordNet®

seal ring
     n : a ring bearing a signet [syn: {signet ring}]