Definition of apatosaur in US English:

apatosaur

(also apatosaurus)

noun

  • A huge herbivorous dinosaur of the late Jurassic period, with a long neck and tail.

    Genus Apatosaurus (popularly Brontosaurus), infraorder Sauropoda, order Saurischia

    Also called brontosaur
    • ‘As Christians who reject evolutionary theory, the family scoffed at the park's dinosaur attractions, which date the apatosaurus, brachiosaurus and the like to prehistoric times.’
    • ‘And one of the marvelous things God described to Job sounds very much like an apatosaurus.’
    • ‘He said continuing research into the species is important because of larger evolutionary questions, including their relationship to the much larger sauropod dinosaurs, including brachiousaurus and apatosaurus.’

Origin

Modern Latin, from Greek apatē ‘deceit’ + sauros ‘lizard’.

Pronunciation

apatosaur

/əˈpatōsôr/