(n) perennial Old World buttercup with golden to sulphur yellow flowers in late spring to early summer; naturalized in North America, Syn. Ranunculus bulbosus
(n) plant of ponds and slow streams having submerged and floating leaves and white flowers; Europe and North America, Syn. water buttercup, Ranunculus aquatilis
The Collaborative International Dictionary of English (GCIDE) v.0.53 Collaborative International Dictionary (GCIDE)
n. (Bot.) A plant of the genus Ranunculus, or crowfoot, particularly Ranunculus bulbosus, with bright yellow flowers; -- called also butterflower, golden cup, and kingcup. It is the cuckoobud of Shakespeare. [ 1913 Webster ]