apatosaurus(n = noun.animal) apatosaur, apatosaurus excelsus, brontosaur, brontosaurus, thunder lizard - huge quadrupedal herbivorous dinosaur common in North America in the late Jurassic;
is a kind of sauropod, sauropod dinosaur
is a member of genus apatosaurus, genus brontosaurus
a genus of extinct dinosaurs comprising the brontosaurs; apatosaurs. [WordNet 1.5]