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

Researchers believe the crest was brightly colored during the dinosaur's lifetime and arched upward like a curved blade, likely serving as a dramatic display structure.

From Science Daily • Feb. 23, 2026

The team found part of the dinosaur's skull, a complete vertebral column extending to the tail, and nearly intact forelimbs and hindlimbs, said CONICET.

From Barron's • Oct. 16, 2025

Experts identified the dinosaur's spine, ribs and a hip bones.

From BBC • Mar. 6, 2025

On a computer screen, the dinosaur’s internal architecture is put back together for the first time in millennia.

From Los Angeles Times • Nov. 15, 2024

And as the kneeling man watched he saw the great red ape who had been dodging his footsteps a short time before, slouch between the dinosaur's hulking body and the wall of the cliff.

From Astounding Stories of Super-Science, October, 1930 by Various