The Collaborative International Dictionary of English v.0.48:
Megalonychidae \Megalonychidae\ prop. n. A natural family consisting of the two-toed sloths. Syn: family Megalonychidae. [WordNet 1.5]WordNet (r) 3.0 (2006):
Megalonychidae n 1: mammal family consisting of the two-toed sloths [syn: Megalonychidae, family Megalonychidae]