The Collaborative International Dictionary of English v.0.48:

Show \Show\, n. [Formerly written also shew.]
   1. The act of showing, or bringing to view; exposure to
      sight; exhibition.
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   2. That which os shown, or brought to view; that which is
      arranged to be seen; a spectacle; an exhibition; as, a
      traveling show; a cattle show.
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            As for triumphs, masks, feasts, and such shows.
                                                  --Bacon.
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   3. Proud or ostentatious display; parade; pomp.
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            I envy none their pageantry and show. --Young.
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   4. Semblance; likeness; appearance.
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            He through the midst unmarked,
            In show plebeian angel militant
            Of lowest order, passed.              --Milton.
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   5. False semblance; deceitful appearance; pretense.
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            Beware of the scribes, . . . which devour widows'
            houses, and for a shew make long prayers. --Luke xx.
                                                  46. 47.
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   6. (Med.) A discharge, from the vagina, of mucus streaked
      with blood, occuring a short time before labor.
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   7. (Mining) A pale blue flame, at the top of a candle flame,
      indicating the presence of fire damp. --Raymond.
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   Show bill, a broad sheet containing an advertisement in
      large letters.

   Show box, a box xontaining some object of curiosity carried
      round as a show.

   Show card, an advertising placard; also, a card for
      displaying samples.

   Show case, a gla?ed case, box, or cabinet for displaying
      and protecting shopkeepers' wares, articles on exhibition
      in museums, etc.

   Show glass, a glass which displays objects; a mirror.

   Show of hands, a raising of hands to indicate judgment; as,
      the vote was taken by a show of hands.

   Show stone, a piece of glass or crystal supposed to have
      the property of exhibiting images of persons or things not
      present, indicating in that way future events.
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WordNet (r) 3.0 (2006):

show card
    n 1: a poster advertising a show or play [syn: show bill,
         show card, theatrical poster]