hadrosaur

from WordNet (r) 3.0 (2006)

hadrosaur
    n 1: any of numerous large bipedal ornithischian dinosaurs
         having a horny duck-like bill and webbed feet; may have
         been partly aquatic [syn: {hadrosaur}, {hadrosaurus},
         {duck-billed dinosaur}]

from The Collaborative International Dictionary of English v.0.48

hadrosaur \hadrosaur\ n.
   Any member of the genus {Hadrosaurus} or family
   {Hadrosauridae}, an extinct family of heavy bipedal partly
   aquatic dinosaurs with duck-billed skull and webbed feet; of
   the Upper Cretaceous in North America.

   Syn: hadrosaurus.
        [WordNet 1.5]