Tyrannosaurus rex

noun

Ty·​ran·​no·​sau·​rus rex tə-ˌra-nə-ˈsȯr-əs-ˈreks 

(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

Volcano clues in enamel Some teeth, including those from Tyrannosaurus rex and the sauropod Kaatedocus siberi, showed unusual isotope signatures. —Neetika Walter, Interesting Engineering, 5 Aug. 2025

Word History

Etymology

New Latin

First Known Use

1905, in the meaning defined above

Rhymes for Tyrannosaurus rex

• annex
• annexe
• apex
• aztecs
• carex
• codecs
• codex
• convex
• cusecs
• duplex
• execs
• fedex