Source : Webster's Revised Unabridged Dictionary (1913)

Kingcup \King"cup`\, n. (Bot.)
   The common buttercup.

Source : WordNet®

kingcup
     n 1: swamp plant of Europe and North America having bright yellow
          flowers resembling buttercups [syn: {marsh marigold}, {meadow
          bright}, {May blob}, {cowslip}, {water dragon}, {Caltha
          palustris}]
     2: any of various plants of the genus Ranunculus [syn: {buttercup},
         {butterflower}, {butter-flower}, {crowfoot}, {goldcup}]