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 a person or thing that is considered to be out of date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

Dinosaur fans had been speculating about the existence of prehistoric creatures in “The End of Oak Street” for months before the world had any proper confirmation.

From Salon • Apr. 12, 2026

Dinosaur fossils preserved with their feathers suggest that some of these animals had already lost the ability to fly.

From Science Daily • Mar. 18, 2026

But then, even the most meticulous research had failed to turn up that Dever’s father, Tim, voiced Bob the Builder, as well as another icon of children’s television, Barney the Dinosaur.

From Los Angeles Times • Jun. 16, 2025

Sweder is the collection manager at the Philip J Currie Dinosaur Museum in nearby Grande Prairie, where the bones from both of these giants are taken to be cleaned up and analysed.

From BBC • May 19, 2025

I would later be awarded the honor of looking after the legal concerns of Barney the Dinosaur.

From "Becoming" by Michelle Obama

Related Words

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• out-of-date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