The dinosaurs are placed, according to their hip structure, in two distantly related orders (see ornithischian and saurischian). Some of them may have been warm-blooded, and their closest living relatives are the birds. Dinosaurs were all extinct by the end of the Cretaceous period (65 million years ago), possibly as a result of a catastrophic asteroid impact in the Gulf of Mexico
mid 19th century: from modern Latin dinosaurus, from Greek deinos 'terrible' + sauros 'lizard'
Spell dinosaur with an o after the n; the ending is -saur.