- any extinct terrestrial reptile of the orders Saurischia and Ornithischia, many of which were of gigantic size and abundant in the Mesozoic era
Compare pterosaur, plesiosaur - a person or thing that is considered to be out of date
WordReference Random House Learner's Dictionary of American English © 2026
di•no•saur /ˈdaɪnəˌsɔr/USA pronunciation
n. [countable]
WordReference Random House Unabridged Dictionary of American English © 2026- Paleontologyany of various plant- or flesh-eating reptiles of prehistoric times, most of which had long tails and were very large.
- something that is too clumsy, out of date, or unable to adapt to change:That old computer is a dinosaur; get a new one.
di•no•saur
(dī′nə sôr′),USA pronunciation n.
- Paleontologyany chiefly terrestrial, herbivorous or carnivorous reptile of the extinct orders Saurischia and Ornithischia, from the Mesozoic Era, certain species of which are the largest known land animals.
- something that is unwieldy in size, anachronistically outmoded, or unable to adapt to change:The old steel mill was a dinosaur that cost the company millions to operate.
- Neo-Latin Dinosaurus (1841), origin, originally a genus name. See dino-, -saur
Collins Concise English Dictionary © HarperCollins Publishers::
dinosaur /ˈdaɪnəˌsɔː/ n
'dinosaur' also found in these entries (note: many are not synonyms or translations):
apatosaurus
- brachiosaurus
- diplodocus
- iguanodon
- megalosaur
- plesiosaur
- pterosaur
- raptor
- -saur
- stegosaur
- triceratops
- tyrannosaurus
- allosaur
- ankylosaur
- armored dinosaur
- bird-footed dinosaur
- brachiosaur
- brontosaur
- camarasaur
- ceratopsian
- ceratosaur
- compsognathus
- deinonychus
- dinosaurian
- Dinosaur National Monument
- duck-billed dinosaur
- hadrosaur
- horned dinosaur
- lizard
- ornithischian
- ornithopod
- prehistoric
- protoavis
- theropod
- titanosaur
- tyrannosaur
- Yampa
- saurian
- saurischian
- sauropod
- supersaur