T. rex
Americannoun
Usage
What is a T. rex? T. rex is short for Tyrannosaurus rex, a giant, meat-eating dinosaur that walked on two legs and had a long tail and a big head with sharp teeth (and, yes, two little arms). The name Tyrannosaurus rex comes from the Greek words tyranno (“tyrant”) and saurus (“lizard”) and the Latin word rex (“king”). So, Tyrannosaurus rex means something like “king of the tyrant lizards.” It is commonly called T. rex for short. The name is fitting: Tyrannosaurus rex is one of the largest land predators that has ever lived. It was the largest of the tyrannosaurs, reaching a length of 47 feet (14. 3 m) or more. People often list the T. rex as their favorite dinosaur, and its popularity has grown through many pop culture depictions, such as its appearances in the Jurassic Park series of movies and books. However, to be scientifically precise about it, the T. rex lived during the Late Cretaceous period, about 90–65 million years ago, around the end of the age of dinosaurs.
Etymology
Origin of T. rex
First recorded in 1980–85; abbreviation of Tyrannosaurus rex ( def. )
Example Sentences
Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.
Other famous mosasaur fossils previously identified as T. proriger are now being reassigned to T. rex.
From Science Daily • May 23, 2026
During that time, I used advanced 3D imaging techniques to examine a T. rex bone and noticed structures that appeared to be blood vessels.
From Science Daily • Apr. 26, 2026
"This small-bodied -- in relation to the T. rex -- meat-eater's hyoid bone showed growth patterns that suggest maturity or approaching maturity," said Poust, Voorhies Endowed Curator of Vertebrate Paleontology.
From Science Daily • Apr. 15, 2026
If anything, after a few days spent dipping my T. rex hands into the cool primordial sludge of the dinosaur fandom, Panella’s sentiment feels like an understatement.
From Salon • Apr. 12, 2026
That foliage could easily hide a T. rex.
From "The Last Cuentista" by Donna Barba Higuera
Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.
