dinosaur

American  

[dahy-nuh-sawr] / ˈdaɪ nəˌsɔr /

noun

• dinosaurs
  plural

1. any 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.

2. 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.

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dinosaur British  

/ ˈdaɪnəˌsɔː /

noun

1. any extinct terrestrial reptile of the orders Saurischia and Ornithischia, many of which were of gigantic size and abundant in the Mesozoic era See also saurischian ornithischian Compare pterosaur plesiosaur

2. a person or thing that is considered to be out of date

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Other Word Forms

Derived Forms

• dinosaurian
  adjective

Inflected Forms

Nouns

• dinosaurs
  plural

Etymology

Origin of dinosaur

< New Latin Dinosaurus (1841), originally a genus name. See dino-, -saur

Explanation

If you've ever seen Jurassic Park, you know that dinosaurs were large reptilian creatures that walked the earth during the Mesozoic era that ran from 245 million to 68 million years ago and included the Triassic, Jurassic, and Cretaceous periods. The ancient Greeks had no knowledge of dinosaurs that we know of, but they unknowingly contributed to the word dinosaur. It was cobbled together in 1841 by British scientist Sir Richard Own, using the words deinos, meaning "terrible" and sauros meaning "lizard." All are gone—at least in their original form, although it is thought they simply evolved into other, present-day animals. The word dinosaur is often used for someone who is old-fashioned or unable to adapt to modern times.

Example Sentences

See Examples For:

dinosaur dinosaurs

Standouts for your weekend watch list: If you’re going to the movies this weekend, check out Anne Hathaway’s new dinosaur film, The End of Oak Street.

From Slate ● Aug. 14, 2026

Using advanced analytical methods, researchers detected remnants of collagen in the hip bone of an Edmontosaurus, a duck billed dinosaur.

From Science Daily ● Aug. 14, 2026

Although it was neither a dinosaur nor a crocodile, it belonged to a lineage closely related to the forms that preceded the origin of these groups.

From Science Daily ● Aug. 10, 2026

Earlier, a number of specimens, including parts of the early dinosaur Thecodontosaurus, were destroyed in Bristol after an Axis raid in 1940.

From Science Daily ● Aug. 7, 2026

All the creatures Kyle had read about and studied in the dinosaur books downstairs were now swarming across the giant video screen in front of him.

From "Mr. Lemoncello's Library Olympics" by Chris Grabenstein

Anne Hathaway and Ewan McGregor star in this charmingly silly film about a suburban family suddenly faced with dinosaurs.

From The Wall Street Journal ● Aug. 13, 2026

And why are man-eating dinosaurs suddenly prowling this ordinary suburb?

From The Wall Street Journal ● Aug. 13, 2026

They and the other dinosaurs — a T. rex, an armored ankylosaurus, a sight-gag-worthy giant snake — adapt to the 20th century as comfortably as coyotes, skulking through backyards in search of prey.

From Los Angeles Times ● Aug. 12, 2026

In other words, the new fossil helps us understand a phase preceding the rise of dinosaurs and crocodiles, when their close relatives were still experimenting with different body shapes, postures, and modes of locomotion.

From Science Daily ● Aug. 10, 2026

Far below us I can see creatures fleeing from the eruption, and even from a distance, it’s clear that they’re dinosaurs.

From "Dragons in a Bag" by Zetta Elliott

Related Words

• antiquated
• archaic
• out-of-date
• outmoded