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 a person or thing that is considered to be out of date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

Derived 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

A dinosaur trackway made up of 200 footprints which were made 166 million years ago is the largest of its kind uncovered in the world, researchers have said.

From BBC • Jun. 10, 2026

And the careful, steadily reported, once-a-week format may seem like a dinosaur in this hyper-paced timeline where deluges of information accost us every ticking second.

From Slate • Jun. 5, 2026

"Kank coexisted with larger carnivores such as Maip macrothorax, a formidable megaraptorid dinosaur more than 10 metres long, which may have been capable of preying upon it," Dr. Motta adds.

From Science Daily • May 29, 2026

A Cervantes video has gone viral for bringing a mini dinosaur named Jerry with him to the mound every time he pitches.

From Los Angeles Times • May 28, 2026

The car bed was neatly made, with a stuffed dinosaur leaning against the pillow, which was in the shape of a tire.

From "Red Kayak" by Priscilla Cummings

Related Words

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• out-of-date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