Source : Webster's Revised Unabridged Dictionary (1913)

Cinquefoil \Cinque"foil`\, n. [Cinque five + foil, F. feuille
   leaf. See {Foil}.]
   1. (Bot.) The name of several different species of the genus
      {Potentilla}; -- also called {five-finger}, because of the
      resemblance of its leaves to the fingers of the hand.

   2. (Arch.) An ornamental foliation having five points or
      cups, used in windows, panels, etc. --Gwilt.

   {Marsh cinquefoil}, the {Potentilla palustris}, a plant with
      purple flowers which grows in fresh-water marshes.

Source : WordNet®

cinquefoil
     n 1: any of a numerous plants grown for their 5-petal flowers;
          abundant in temperate regions; alleged to have medicinal
          properties [syn: {five-finger}]
     2: an ornamental carving consisting of five arcs arranged in a
        circle