di·​no·​saur | \ ˈdī-nə-ˌsȯr How to pronounce dinosaur (audio) \

Definition of dinosaur

1 : any of a group (Dinosauria) of extinct often very large chiefly terrestrial carnivorous or herbivorous reptiles of the Mesozoic era
2 : any of various large extinct reptiles (such as ichthyosaurs) other than the true dinosaurs
3 : one that is impractically large, out-of-date, or obsolete The factory is now a rusting dinosaur.

Keep scrolling for more

Other Words from dinosaur

dinosaurian \ ˌdī-​nə-​ˈsȯr-​ē-​ən How to pronounce dinosaurian (audio) \ adjective
dinosauric \ ˌdī-​nə-​ˈsȯr-​ik How to pronounce dinosauric (audio) \ adjective

Synonyms for dinosaur


has-been, relic

Visit the Thesaurus for More 

Examples of dinosaur in a Sentence

The old factory is now a rusting dinosaur. The character she plays is a dinosaur—a former beauty queen who is living in the past.

Recent Examples on the Web

But Steven Spielberg‘s version, of course, included dinosaurs, as a group of humans volunteered to leave a dystopian future to live on a parallel time stream planet that resembles Earth 85 million years ago, a.k.a. Sydney Bucksbaum, EW.com, "Netflix's The I-Land tries (and fails) to be the next Lost — just like these 11 other shows," 14 Sep. 2019 Yale Peabody Museum of Natural History, 170 Whitney Ave. in New Haven, 10 a.m. to 5 p.m. Exhibits on ancient Mesopotamia, saltwater fly fishing, California gold, beads, dinosaurs, ancient Egypt, birds of Connecticut and minerals. Susan Dunne, courant.com, "You’ll get in free at these 24 Connecticut arts and culture venues on Museums Day," 12 Sep. 2019 For his part, Michael regards his new guardian as a dinosaur, hopelessly ignorant of anything that matters, like tennis shoes or selfies. Ron Charles Critic, Washington Post, "Emma Donoghue’s ‘Akin’ sends an odd couple to France," 10 Sep. 2019 But when Holliday studied these skull spaces in dinosaurs, alligators, and other animals, the old explanation didn’t add up. John Pickrell, National Geographic, "New discovery shows how T. rex kept its brain cool," 4 Sep. 2019 Anything will do: A toy dinosaur, a headless Superman, a bowling pin — all are set up in artistic displays along the narrow trail. Cnn.com Wire Service, The Mercury News, "This might be the creepiest hike you’ll ever go on," 15 Aug. 2019 The dinosaur, which shares features with other members of the Saurolophidae family (like duck bills and crested heads) has a primitive facial structure that may hint at how Saurolophidae evolved. Daisy Hernandez, Popular Mechanics, "This Duck-Billed Dino Is One Weird-Looking Creature," 18 July 2019 During the days of the dinosaurs, the Jurassic and Cretaceous periods, crocodile-clan members showed extraordinary dental diversity. The Economist, "Vegetarian crocodiles once roamed the world," 28 June 2019 But her new storyline is akin to what killed the dinosaurs: chaos. Lee Williams | For The Oregonian/oregonlive, oregonlive.com, "‘Heathers: The Musical’ puts Generation X nostalgia front and center," 24 June 2019

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'dinosaur.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

See More

First Known Use of dinosaur

1841, in the meaning defined at sense 1

History and Etymology for dinosaur

New Latin Dinosaurus, genus name, from Greek deinos terrifying + sauros lizard — more at dire

Keep scrolling for more

Learn More about dinosaur

Statistics for dinosaur

Last Updated

26 Sep 2019

Look-up Popularity

Time Traveler for dinosaur

The first known use of dinosaur was in 1841

See more words from the same year

Keep scrolling for more

More Definitions for dinosaur



English Language Learners Definition of dinosaur

: one of many reptiles that lived on Earth millions of years ago
: someone or something that is no longer useful or current : an obsolete or out-of-date person or thing


di·​no·​saur | \ ˈdī-nə-ˌsȯr How to pronounce dinosaur (audio) \

Kids Definition of dinosaur

: any of a group of extinct often very large mostly land-dwelling reptiles that lived millions of years ago

Keep scrolling for more

Comments on dinosaur

What made you want to look up dinosaur? Please tell us where you read or heard it (including the quote, if possible).


to fake an opponent out of position

Get Word of the Day daily email!

Test Your Vocabulary

Where in the World? A Quiz

  • peter bruegel tower of babel painting
  • What language does pajama come from?
Spell It

Can you spell these 10 commonly misspelled words?


Test Your Knowledge - and learn some interesting things along the way.

Love words? Need even more definitions?

Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free!