genus Hyracotherium ge·nus·hy·racotherium uncommon noun 1. extinct horse genus; formerly called genus Eohippus SynonymsHyracotheriumgenus Hyracotherium Related words Broader terms mammal genus Parts Equidae Part of eohippus WordNet 2.1 (Princeton University). WordNet 2.1 Copyright Princeton University. All rights reserved.
