The Collaborative International Dictionary of English v.0.48:
Mylodon \Myl"o*don\, n. [Gr. ? a mill + 'odoy`s, 'odo`ntos, a tooth.] (Paleon.) An extinct genus of large slothlike American edentates, allied to Megatherium. [1913 Webster]WordNet (r) 3.0 (2006):
mylodon n 1: large (bear-sized) extinct edentate mammal of the Pleistocene in South America