The Collaborative International Dictionary of English v.0.48:

Hadrosauridae \Hadrosauridae\ prop. n.
   A natural family of extinct reptiles including the
   duck-billed dinosaurs.

   Syn: family Hadrosauridae.
        [WordNet 1.5]

WordNet (r) 3.0 (2006):

Hadrosauridae
    n 1: duck-billed dinosaurs; upper Cretaceous [syn:
         Hadrosauridae, family Hadrosauridae]