dinosaur

American  

[dahy-nuh-sawr] / ˈdaɪ nəˌsɔr /

noun

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 a person or thing that is considered to be out of date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

• dinosaurian
  adjective

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

Other species to have been named after the broadcaster in the past include a wildflower, butterfly, grasshopper, dinosaur and ghost shrimp.

From BBC • May 7, 2026

With the combination of physics, paleontology, and advanced imaging technologies, researchers are beginning to uncover details about dinosaur biology that were once thought impossible to study.

From Science Daily • Apr. 26, 2026

This work may also provide a basis for comparison with other dinosaur species and with modern animals such as birds, which are closely related to dinosaurs.

From Science Daily • Apr. 26, 2026

Among them are the first dinosaur identified in the southern hemisphere, now known to be a stegosaur, along with sauropods, a coelurosaurian, and young iguanodontids.

From Science Daily • Apr. 24, 2026

She runs for her squeaky dinosaur and sticks it in my face.

From "The Tenth Mistake of Hank Hooperman" by Gennifer Choldenko

Related Words

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• out-of-date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