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(Palaeontology) any of various gigantic extinct American sloths of the genus Megatherium and related genera, common in late Cenozoic times
[C19: from New Latin megathērium, from mega- + -there, from Greek thērion wild beast]
any of the huge slothlike animals of the extinct genus Megatherium or closely related genera that lived from the Oligocene to the Pleistocene epochs.
[1830–40; < New Latin]