The Collaborative International Dictionary of English v.0.48:

Hyperodontidae \Hyperodontidae\ prop. n.
   A natural family of cetaceans comprising the beaked whales;
   in some, especially former, classifications it included in
   the family Physeteridae.

   Syn: Ziphiidae, family Ziphiidae, family Hyperodontidae.
        [WordNet 1.5]

WordNet (r) 3.0 (2006):

Hyperodontidae
    n 1: beaked whales; in some especially former classifications
         included in the family Physeteridae [syn: Ziphiidae,
         family Ziphiidae, Hyperodontidae, family
         Hyperodontidae]