Tyrannosaurus rex

noun

Ty·​ran·​no·​sau·​rus rex tə-ˌra-nə-ˈsȯr-əs-ˈreks How to pronounce Tyrannosaurus rex (audio)
(ˌ)tī-
variants or Tyrannosaurus Rex or less commonly Tyrannosaurus or tyrannosaurus or tyrannosaurus rex
plural Tyrannosaurus rexes or Tyrannosaurus Rexes also Tyrannosauruses or tyrannosauruses or tyrannosaurus rexes
: a massive North American bipedal tyrannosaurid dinosaur (Tyrannosaurus rex) of the late Cretaceous with a large skull, heavy tail, and reduced forelimbs having two clawed digits : tyrannosaur sense 1
Tyrannosaurus rex was … one of the biggest meat-eaters ever. It was over 40 feet tall, and weighed up to 7 tons!Wendy Larson
A study of the running ability of Tyrannosaurus Rex … suggests that the king of the prehistoric jungle wasn't quite the speedster we once thought.Andrea Dorfman et al.
During this period, many groups of dinosaurs, including the fearsome tyrannosaurus and the three-horned triceratops, reached their greatest size, 12 meters (40 feet) and 9 meters (30 feet) long, respectively.Joseph Wallace
… in a room full of Tyrannosaurus rexes I meet museum volunteers … who are using brushes and tiny picks on fossils in an area where people can watch and ask questions.Mel White
True, there may no longer be actual tyrannosauruses running amok, but there are still dinosaur descendants hanging around, and they may even be in your backyard: birds, of course!Emily Graham

called also T. rex

Examples of Tyrannosaurus rex in a Sentence

Recent Examples on the Web
Examples are automatically compiled from online sources to show current usage. Read More Opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback.
In light of the parking lot discovery, paleontologists were inspired to go back and look at available satellite and elevation data to date all other fossils previously found within the Denver metro area, including a Tyrannosaurus rex, Triceratops and Torosaurus, and other major fossil deposits. Taylor Nicioli, CNN Money, 17 July 2025 Instead of snowy mountains, tropical rainforests and swampy lowland floodplains covered Colorado with dinosaurs like the Tyrannosaurus rex roaming around. Andrew Paul Jul 10, Popular Science, 10 July 2025 The fossil is also similar to the herbivore edmontosaurus, a larger four-legged dinosaur that roamed the region alongside fierce predators like the Tyrannosaurus rex. Katie Langford, Denver Post, 9 July 2025 The offerings include a Late Neolithic stone axe, the skeleton of a 150-million-year-old juvenile Ceratosaurus dinosaur, an articulated Tyrannosaurus rex foot and other fossils. Sarah Kuta, Smithsonian Magazine, 8 July 2025 Sue is physically the largest Tyrannosaurus rex specimen ever discovered. Rona Berg, Forbes.com, 27 June 2025 The crocs wandering the prehistoric Dominican Republic five million years ago were descended from carnivores that evolved back when dinosaurs like Tyrannosaurus rex still roamed the planet. Riley Black, Smithsonian Magazine, 25 June 2025 Paleontologists have discovered a new species of dinosaur that was related to the infamous Tyrannosaurus rex. Julia Jacobo, ABC News, 11 June 2025 One more migration happened as tyrannosaurs continued to evolve, and a gigantic tyrannosaur species crossed back into North America 68 million years ago, resulting in Tyrannosaurus rex, Zelenitsky said. Ashley Strickland, CNN Money, 11 June 2025

Word History

Etymology

New Latin

First Known Use

1905, in the meaning defined above

Time Traveler
The first known use of Tyrannosaurus rex was in 1905

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Cite this Entry

“Tyrannosaurus rex.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/Tyrannosaurus%20rex. Accessed 25 Jul. 2025.

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