Definition of pachycephalosaur in US English:

pachycephalosaur

noun

  • A bipedal herbivorous dinosaur of the late Cretaceous period, with a thick domed skull.

    Infraorder Pachycephalosauria, order Ornithischia: several genera, including Pachycephalosaurus

    • ‘More recently, paleontologists have suggested that other dinosaurs, notably the dome-headed pachycephalosaurs, also used their cranial appendages defensively.’
    • ‘The domed skulls of pachycephalosaurs may likewise have been vibrantly colored to indicate sexual maturity, attract a mate, or warn an adversary.’
    • ‘An alternate view, that ceratopsians and pachycephalosaurs diverged from ornithopod dinosaurs in the Late Jurassic, is more consistent with the preserved biostratigraphic evidence.’
    • ‘Marginocephalia consists mainly of the pachycephalosaurs (bone-heads) and the ceratopsians (horned dinosaurs), like Triceratops.’
    • ‘The already diverse and abundant record of dinosaur skeletal fossils was increased by the discovery in 1999 of the first evidence of pachycephalosaurs from this region.’

Origin

From Greek pakhus ‘thick’ + kephalē ‘head’ + sauros ‘lizard’.

Pronunciation

pachycephalosaur

/ˌpakiˈsefələsôr/