The Collaborative International Dictionary of English v.0.48:
Ornithorhynchidae \Ornithorhynchidae\ prop. n. The natural family of monotremes including the platypus (duckbill) (Ornithorhyncus anatinus). Syn: family Ornithorhynchidae. [WordNet 1.5]WordNet (r) 3.0 (2006):
Ornithorhynchidae n 1: platypus [syn: Ornithorhynchidae, family Ornithorhynchidae]