any of various water lilies of the genus Nuphar, having globular yellow flowers and growing in lakes or sluggish streams, esp. N. advena, of the eastern U.S.
spat·ter·dock (spāt'ər-dŏk') n. An aquatic plant (Nuphar advena) of eastern Mexico and the eastern and central United States, having emergent broad leaves and globe-shaped yellow flowers.