Source : Webster's Revised Unabridged Dictionary (1913)

Spatter-dock \Spat`ter-dock`\, n. (Bot.)
   The common yellow water lily ({Nuphar advena}).

Source : WordNet®

Nuphar advena
     n : common water lily of eastern and central North America,
         having broad leaves and globe-shaped yellow flowers; in
         sluggish fresh or slightly brackish water [syn: {spatterdock},
          {cow lily}, {yellow pond lily}]