Definition of "Dinosauria"

A taxonomic superorder within the division Archosauria – true dinosaurs, including modern birds; a clade of ornithodiran archosaurian diapsid reptilians, distinguished by their hip bones, erect hind limbs and shorter forearms, and differentiated from the pterosaurs and other dinosauromorphs. First appearing in the Triassic, they became a polymorphic and widespread group, but only the avian line avoided extinction at the end of the Cretaceous.  examples