dinosaur

noun
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, carnivorous or herbivorous archosaurian reptiles that have the hind limbs extending directly beneath the body and include chiefly terrestrial, bipedal or quadrupedal ornithischians (such as ankylosaurs and stegosaurs) and saurischians (such as sauropods and theropods) which flourished during the Mesozoic era from the late Triassic period to the end of the Cretaceous period The dinosaurs, which once dominated the earth, disappeared very swiftly, leaving room for tiny shrewlike creatures to crawl out of shelter and start on the road to mammalian domination of the planet.— D. E. Thomsen Most scientists now concur that at least one great extraterrestrial object struck the planet around the time the dinosaurs died out.— Rick Gore also : any of a broader group that also includes all living and extinct birds The overwhelming majority of scientists are now convinced that birds are theropod dinosaurs— James O'Donoghue

Note: Dinosaurs have traditionally been considered a separate group from birds, which evolved from dinosaurs, but modern paleontologists now view birds as survivors of a theropod lineage of dinosaurs. In this classification, all dinosaurs except birds became extinct at the end of the Cretaceous period approximately 65 million years ago, with all dinosaurs that are not birds referred to as dinosaurs or non-avian dinosaurs and birds typically referred to as avian dinosaurs.

2 : any of various large extinct reptiles (such as an ichthyosaur or mosasaur) other than the true dinosaurs
3 : one that is impractically large, out-of-date, or obsolete The factory is now a rusting dinosaur.

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Other Words from dinosaur

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

Synonyms for dinosaur

Synonyms

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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 One man was dressed as a strip of bacon, and another came as a purple dinosaur. Maggie Menderski, The Courier-Journal, 27 Sep. 2021 Basically, the Big 12 was viewed as a dinosaur and the Texas and OU move appeared to be the asteroid smashing into Yucatan. Chuck Carlton, Dallas News, 10 Sep. 2021 The circa 1932 cabin located five miles west of Medicine Bow, Wyoming, along Lincoln Highway, is comprised of nearly 5,800 fossilized dinosaur bones and is the creation of Thomas Boylan, a local cattle rancher. Jennifer Nalewicki, Smithsonian Magazine, 29 June 2021 An 11-foot-high dinosaur in kaleidoscopic colors, made of 182,000 Lego bricks? New York Times, 1 Oct. 2021 To its detractors, meanwhile, the Peace Corps is a dinosaur, a Cold War-era diplomacy project that has outlived its usefulness. Nick Roll, The Christian Science Monitor, 22 Sep. 2021 And for dinosaur fans, there’s time for fossil hunting. Los Angeles Times, 29 Oct. 2020 There are many companies that lacked the data and foresight to adapt in the way Sharp did, and subsequently went the way of the dinosaur. Hayley Selby, Forbes, 16 Sep. 2021 Researchers have discovered a new species of dinosaur that loomed over Tyrannosaurus Rex. Greta Bjornson, PEOPLE.com, 10 Sep. 2021

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.

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First Known Use of dinosaur

1841, in the meaning defined at sense 1

History and Etymology for dinosaur

borrowed from presumed New Latin *dinosaurus, the base of Dinosauria, former reptile taxon, from Greek deinós "inspiring dread or awe" + -o- -o- + New Latin Sauria, former reptile suborder, from Greek saúros "lizard" + New Latin -ia -ia entry 2 — more at deinonychus, -saurus

Note: The taxonomic name Dinosauria as well as the vernacular form dinosaur were both introduced by the British biologist and paleontologist Richard Owen (1804-92) in "Report on British Fossil Reptiles. Part II," Report of the Eleventh Meeting of the British Association for the Advancement of Science ("Held at Plymouth in July 1841") (London: J. Murray, 1842), p. 103: "The combination of such characters, some, as the sacral ones [i.e., the sacral vertebrae fused into a single structure], altogether peculiar among Reptiles, others borrowed, as it were, from groups now distinct from each other, and all manifested by creatures far surpassing in size the largest of existing reptiles, will, it is presumed, be deemed sufficient ground for establishing a distinct tribe or sub-order of Saurian Reptiles, for which I would propose the name of Dinosauria. [Footnote to the above] Gr. deinòs, fearfully great; saúros, a lizard." Although Owen's "Report on British Fossil Reptiles" purports to be the record of an oral presentation given at Plymouth in July, 1841, the detailed contemporary accounts of Owen's lecture do not mention dinosaur or Dinosauria, and it is now clear that he only introduced the word with the extensively revised version of the report released in April, 1842. The background to Owen's report is analyzed by Hugh S. Torrens in "Politics and Paleontology: Richard Owen and the Invention of Dinosaurs," M. K. Brett-Surman, et al., editors, The Complete Dinosaur, 2nd edition (Indiana University Press, 2012), pp. 25-43. Offprints of Owen's article have the publication date 1841, but, as Torrens demonstrates (p. 34), this was an error (perhaps deliberately uncorrected by Owen). Owen's rendering of Greek deinós (a word with a wide semantic range) as "fearfully great" is at odds with the conventional notion that dinosaur means "terrible lizard" in Greek. Although "terrible" (i.e., terrifying) is a possible translation of deinós, it does not appear to be the meaning Owen intended.

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The first known use of dinosaur was in 1841

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Dictionary Entries Near dinosaur

Dinornithidae

dinosaur

Dinosauria

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Last Updated

18 Oct 2021

Cite this Entry

“Dinosaur.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/dinosaur. Accessed 27 Oct. 2021.

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More Definitions for dinosaur

dinosaur

noun

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

dinosaur

noun
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

More from Merriam-Webster on dinosaur

Nglish: Translation of dinosaur for Spanish Speakers

Britannica English: Translation of dinosaur for Arabic Speakers

Britannica.com: Encyclopedia article about dinosaur

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