dinosaurs

Cultural  

1. Reptiles, now extinct, that were the dominant life form on Earth for many millions of years. The name dinosaur comes from the Greek words for “monstrous lizard.” Dinosaurs became extinct suddenly, about sixty-five million years ago. Scientists now believe that their extinction was caused by the impact of a large asteroid on the Earth.

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Some dinosaurs were very large and had small brains — factors that may in part have led to their extinction. The term is often used to refer to something or someone that is antiquated and unable to adapt to change: “The old cavalry generals couldn't adjust to the use of tanks — they became dinosaurs.”

Some scientists believe that modern birds are the descendants of dinosaurs.

Commonly known dinosaurs include Tyrannosaurus rex, Brontosaurus, Stegosaurus, and Triceratops.

Example Sentences

Living in the eastern United States between 83 million and 76 million years ago, Deinosuchus schwimmeri was a school-bus-sized relative of modern alligators that preyed on dinosaurs.

From Science Daily • Apr. 15, 2026

After years of analysis, the team determined that this dinosaur belonged to Herrerasauria, one of the earliest groups of carnivorous dinosaurs.

From Science Daily • Apr. 15, 2026

Does the reason I’m interested in “The End of Oak Street” have just as much to do with the dinosaurs as it does Anne “Ally” Hathaway?

From Salon • Apr. 12, 2026

When Choudhury posts about which dinosaurs his followers want to see in the film, his replies are quickly inundated with scientific renderings of all kinds of giant beasts.

From Salon • Apr. 12, 2026

No one knows what wiped out the dinosaurs.

From "Cosmos" by Carl Sagan