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 a person or thing that is considered to be out of date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

In a study published in the Annals of Carnegie Museum, researchers report the discovery of a previously unknown dinosaur species from the same fossil bed.

From Science Daily • Jun. 23, 2026

One controversial proposal suggests that several smaller fossils represent a separate dinosaur called Nanotyrannus rather than young Tyrannosaurus individuals.

From Science Daily • Jun. 22, 2026

A dinosaur trackway made up of 200 footprints which were made 166 million years ago is the largest of its kind uncovered in the world, researchers have said.

From BBC • Jun. 10, 2026

And the careful, steadily reported, once-a-week format may seem like a dinosaur in this hyper-paced timeline where deluges of information accost us every ticking second.

From Slate • Jun. 5, 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

Related Words

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• out-of-date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