American Heritage Dictionary
Century Dictionary
GNU Webster's 1913
WordNet
(1)
Elsewhere on the web
The Panhypocrisiade of Lemercier, published in 1819, but written several years earlier--an "infernal comedy of the sixteenth century"--is an amazing chaos of extravagance, incompetence, and genius; it bears to Hugo's Lιgende des Siθcles the relation which the megatherium or mastodon may bear to some less monstrous analogues If we are to look for a presentiment of Lamartine's poetry, we may find it in the harmonious melancholy of Chκnedollι, in the grace of Fontanes' stanzas, in the timid elegiac strains of Millevoye.— A History of French Literature Short Histories of the Literatures of the World: II.
"[129 The context proves Buffon to have been thinking of such huge creatures as the megatherium and mastodon, but his words seem to limit the extinction of species to the denizens of a hot climate which had turned colder.— Evolution, Old ; New Or, the Theories of Buffon, Dr. Erasmus Darwin and Lamarck, as compared with that of Charles Darwin
The megatherium is an incongruity of nature, of gigantic proportions, yet ranking in a much humbler order than the elephant, that of the edenta, to which the sloth, ant-eater, and armadilla belong.— An Expository Outline of the "Vestiges of the Natural History of Creation" With a Notice of the Author's "Explanations:" A Sequel to the Vestiges
All these atrocities and follies amuse and interest us now; they are the coprolites of a literary megatherium, once hateful to gods and men, now inoffensive and curious fossilized specimens In 1863, a Scotchman, whom Dr. Johnson would have hated for his birth, and have knocked down with his Dictionary for his assaults upon the English language, has usurped the chair of the sturdy old dogmatist.— The Atlantic Monthly, Volume 13, No. 78, April, 1864
The megatherium is described zoologically as having combined the characteristics of the armadillo, sloth, and ant-eater.— How to See the British Museum in Four Visits

If you'd like to prod us on getting a pronunciation for this word, sign in (or sign up) and let us know.
Bubble size: how much this word was used in a year
Bubble height: used more or less than expected, vs. all uses evenly distributed
You can expect to see this word about once a year.