The Collaborative International Dictionary of English v.0.48:

Patent \Pat"ent\ (p[a^]t"ent or p[=a]t"ent), a. [L. patens,
   -entis, p. pr. of patere to be open: cf. F. patent. Cf.
   Fathom.]
   1.

   Note: (Oftener pronounced p[=a]t"ent in this sense) Open;
         expanded; evident; apparent; unconcealed; manifest;
         public; conspicuous.
         [1913 Webster]

               He had received instructions, both patent and
               secret.                            --Motley.
         [1913 Webster]

   2. Open to public perusal; -- said of a document conferring
      some right or privilege; as, letters patent. See Letters
      patent, under 3d Letter.
      [1913 Webster]

   3. Appropriated or protected by letters patent; secured by
      official authority to the exclusive possession, control,
      and disposal of some person or party; patented; as, a
      patent right; patent medicines.
      [1913 Webster]

            Madder . . . in King Charles the First's time, was
            made a patent commodity.              --Mortimer.
      [1913 Webster]

   4. (Bot.) Spreading; forming a nearly right angle with the
      steam or branch; as, a patent leaf.
      [1913 Webster]

   Patent leather, a varnished or lacquered leather, used for
      boots and shoes, and in carriage and harness work.

   Patent office, a government bureau for the examination of
      inventions and the granting of patents.

   Patent right.
      (a) The exclusive right to an invention, and the control
          of its manufacture.
      (b) (Law) The right, granted by the sovereign, of
          exclusive control of some business of manufacture, or
          of the sale of certain articles, or of certain offices
          or prerogatives.

   Patent rolls, the registers, or records, of patents.
      [1913 Webster]

WordNet (r) 3.0 (2006):

Patent Office
    n 1: the government bureau in the Department of Commerce that
         keeps a record of patents and trademarks and grants new
         ones [syn: Patent and Trademark Office Database, Patent
         Office]