The Collaborative International Dictionary of English v.0.48:

Paper \Pa"per\ (p[=a]"p[~e]r), n. [F. papier, fr. L. papyrus
   papyrus, from which the Egyptians made a kind of paper, Gr.
   pa`pyros. Cf. Papyrus.]
   1. A substance in the form of thin sheets or leaves intended
      to be written or printed on, or to be used in wrapping. It
      is made of rags, straw, bark, wood, or other fibrous
      material, which is first reduced to pulp, then molded,
      pressed, and dried.
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   2. A sheet, leaf, or piece of such substance.
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   3. A printed or written instrument; a document, essay, or the
      like; a writing; as, a paper read before a scientific
      society.
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            They brought a paper to me to be signed. --Dryden.
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   4. A printed sheet appearing periodically; a newspaper; a
      journal; as, a daily paper.
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   5. Negotiable evidences of indebtedness; notes; bills of
      exchange, and the like; as, the bank holds a large amount
      of his paper.
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   6. Decorated hangings or coverings for walls, made of paper.
      See Paper hangings, below.
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   7. A paper containing (usually) a definite quantity; as, a
      paper of pins, tacks, opium, etc.
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   8. A medicinal preparation spread upon paper, intended for
      external application; as, cantharides paper.
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   9. pl. Documents establishing a person's identity, or status,
      or attesting to some right, such as the right to drive a
      vehicle; as, the border guard asked for his papers.
      [PJC]

   Note: Paper is manufactured in sheets, the trade names of
         which, together with the regular sizes in inches, are
         shown in the following table. But paper makers vary the
         size somewhat.
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   Note: In the manufacture of books, etc., a sheet, of whatever
         size originally, is termed, when folded once, a folio;
         folded twice, a quarto, or 4to; three times, an octavo,
         or 8vo; four times, a sextodecimo, or 16mo; five times,
         a 32mo; three times, with an offcut folded twice and
         set in, a duodecimo, or 12mo; four times, with an
         offcut folded three times and set in, a 24mo.
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   Note: Paper is often used adjectively or in combination,
         having commonly an obvious signification; as, paper
         cutter or paper-cutter; paper knife, paper-knife, or
         paperknife; paper maker, paper-maker, or papermaker;
         paper mill or paper-mill; paper weight, paper-weight,
         or paperweight, etc.
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   Business paper, checks, notes, drafts, etc., given in
      payment of actual indebtedness; -- opposed to
      accommodation paper.

   Fly paper, paper covered with a sticky preparation, -- used
      for catching flies.

   Laid paper. See under Laid.

   Paper birch (Bot.), the canoe birch tree (Betula
      papyracea).

   Paper blockade, an ineffective blockade, as by a weak naval
      force.

   Paper boat (Naut.), a boat made of water-proof paper.

   Paper car wheel (Railroad), a car wheel having a steel
      tire, and a center formed of compressed paper held between
      two plate-iron disks. --Forney.

   Paper credit, credit founded upon evidences of debt, such
      as promissory notes, duebills, etc.

   Paper hanger, one who covers walls with paper hangings.

   Paper hangings, paper printed with colored figures, or
      otherwise made ornamental, prepared to be pasted against
      the walls of apartments, etc.; wall paper.

   Paper house, an audience composed of people who have come
      in on free passes. [Cant]

   Paper money, notes or bills, usually issued by government
      or by a banking corporation, promising payment of money,
      and circulated as the representative of coin.

   Paper mulberry. (Bot.) See under Mulberry.

   Paper muslin, glazed muslin, used for linings, etc.

   Paper nautilus. (Zool.) See Argonauta.

   Paper reed (Bot.), the papyrus.

   Paper sailor. (Zool.) See Argonauta.

   Paper stainer, one who colors or stamps wall paper. --De
      Colange.

   Paper wasp (Zool.), any wasp which makes a nest of
      paperlike material, as the yellow jacket.

   Paper weight, any object used as a weight to prevent loose
      papers from being displaced by wind, or otherwise.

   on paper.
      (a) in writing; as, I would like to see that on paper.
      (b) in theory, though not necessarily in paractice.
      (c) in the design state; planned, but not yet put into
          practice.

   Parchment paper. See Papyrine.

   Tissue paper, thin, gauzelike paper, such as is used to
      protect engravings in books.

   Wall paper. Same as Paper hangings, above.

   Waste paper, paper thrown aside as worthless or useless,
      except for uses of little account.

   Wove paper, a writing paper with a uniform surface, not
      ribbed or watermarked.

   paper tiger, a person or group that appears to be powerful
      and dangerous but is in fact weak and ineffectual.
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WordNet (r) 3.0 (2006):

paper money
    n 1: currency issued by a government or central bank and
         consisting of printed paper that can circulate as a
         substitute for specie [syn: paper money, folding money,
         paper currency]