The Collaborative International Dictionary of English v.0.48:

Nelumbo \Ne*lum"bo\, prop. n. [Ceylonese word.] (Bot.)
   A genus of great water lilies. The North American species is
   Nelumbo lutea, the Asiatic is the sacred lotus, Nelumbo
   speciosa. [Written also Nelumbium.]
   [1913 Webster]

WordNet (r) 3.0 (2006):

Nelumbo
    n 1: sometimes placed in the family Nymphaeaceae: lotuses [syn:
         Nelumbo, genus Nelumbo]