The Collaborative International Dictionary of English v.0.48:

Cardinal \Car"di*nal\, n. [F. carinal, It. cardinale, LL.
   cardinalis (ecclesi[ae] Roman[ae]). See Cardinal, a.]
   1. (R. C. Ch.) One of the ecclesiastical princes who
      constitute the pope's council, or the sacred college.
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            The clerics of the supreme Chair are called
            Cardinals, as undoubtedly adhering more nearly to
            the hinge by which all things are moved. --Pope Leo
                                                  IX.
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   Note: The cardinals are appointed by the pope. Since the time
         of Sixtus V., their number can never exceed seventy
         (six of episcopal rank, fifty priests, fourteen
         deacons), and the number of cardinal priests and
         deacons is seldom full. When the papel chair is vacant
         a pope is elected by the college of cardinals from
         among themselves. The cardinals take precedence of all
         dignitaries except the pope. The principal parts of a
         cardinal's costume are a red cassock, a rochet, a short
         purple mantle, and a red hat with a small crown and
         broad brim, with cords and tessels of a special pattern
         hanging from it.
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   2. A woman's short cloak with a hood.
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            Where's your cardinal! Make haste.    --Lloyd.
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   3. Mulled red wine. --Hotten.
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   4. the cardinal bird, also called the northern cardinal.
      [PJC]

   Cardinal bird, or Cardinal grosbeak (Zool.), an American
      song bird (Cardinalis cardinalis, or Cardinalis
      Virginianus), of the family Fringillid[ae], or finches
      of which the male has a bright red plumage, and both sexes
      have a high, pointed crest on its head; -- it is also
      called the northern cardinal or eastern cardinal. The
      males have loud and musical notes resembling those of a
      fife. Other related species are also called cardinal
      birds.

   Cardinal flower (Bot.), an herbaceous plant (Lobelia
      cardinalis) bearing brilliant red flowers of much beauty.


   Cardinal red, a color like that of a cardinal's cassock,
      hat, etc.; a bright red, darker than scarlet, and between
      scarlet and crimson.
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WordNet (r) 3.0 (2006):

cardinal flower
    n 1: North American lobelia having brilliant red flowers [syn:
         cardinal flower, Indian pink, Lobelia cardinalis]