Table of Contents
Fast Facts
Read Next
Quizzes
Science & Tech
dinosaur
fossil reptile
Feedback
Thank you for your feedback
Our editors will review what you’ve submitted and determine whether to revise the article.
External Websites
Britannica Websites
Articles from Britannica Encyclopedias for elementary and high school students.
Category:
Science & Tech
- Related Topics:
- saurischian ornithischian theropod cerapod Sauropodomorpha
Recent News
Jul. 18, 2023, 11:11 AM ET (AP)
Mammals may have hunted down dinosaurs for dinner, rare fossil suggests
Top Questions
What are dinosaurs?
How did most dinosaurs go extinct?
Did dinosaurs have feathers?
Do dinosaurs exist today?
What is the largest dinosaur?
When was the first dinosaur fossil discovered?
dinosaur, (clade Dinosauria), the common name given to a group of reptiles, often very large, that first appeared roughly 245 million years ago (near the beginning of the Middle Triassic Epoch) and thrived worldwide for nearly 180 million years. Most died out by the end of the Cretaceous Period, about 66 million years ago, but many lines of evidence now show that one lineage evolved into birds about 155 million years ago. (Read E.O. Wilson’s Britannica essay on mass extinction.) The name dinosaur comes from the Greek words deinos (“terrible” or “fearfully great”) and sauros (“reptile” or “lizard”). The English ...(100 of 18542 words)