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.

---

Discover More

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

Fast facts: A sci-fi thrill ride starring Anne Hathaway and Ewan McGregor as parents who have to fight for their lives when their whole street is mysteriously transported to a world with dinosaurs.

From The Wall Street Journal • Jun. 6, 2026

Researchers classified the dinosaur as an unenlagiid, a group of small to medium sized theropod dinosaurs known from Late Cretaceous rocks in South America, Antarctica, Australia, and Madagascar.

From Science Daily • May 29, 2026

In George Redfox’s photography class, Cervantes and his classmates were assigned to take pictures of mini dinosaurs on the ground at varying angles.

From Los Angeles Times • May 29, 2026

This small group of ancient crocodile relatives evolved body plans that closely resembled bipedal theropod dinosaurs, despite belonging to a very different branch of the reptile family tree.

From Science Daily • May 29, 2026

And dinosaurs standing around drinking coffee, staring up at the giant meteor soaring through the air, commenting on how pretty it is.

From "Fish in a Tree" by Lynda Mullaly Hunt