Cretaceous

adjective

Cre·​ta·​ceous kri-ˈtā-shəs 

: of, relating to, or being the last period of the Mesozoic era characterized by continued dominance of reptiles, emergent dominance of angiosperms, diversification of mammals, and the extinction of many types of organisms at the close of the period

also : of, relating to, or being the corresponding system of rocks see Geologic Time Table

Cretaceous noun

Examples of Cretaceous in a Sentence

Recent Examples on the Web

To find answers, a team of scientists studied North America’s fossil record, focusing on the 18 million years before the mass extinction at the end of the Cretaceous period. —Kimberly Richardson, CNN Money, 15 Apr. 2025

The researchers then estimated the likelihood of each of the dinosaur clades occupying the different grid cells at four time points within the final 18 million years of the Cretaceous period. —Rosie McCall, Discover Magazine, 8 Apr. 2025

Mammals Adapted to the Ground When the asteroid arrived at the end of the Cretaceous period, the dinosaurs disappeared. —Sam Walters, Discover Magazine, 2 Apr. 2025

Paleontologists studied 16 specimens of the tiny wasp preserved in amber dating back to the Cretaceous period that was previously unearthed in Myanmar. —Katie Hunt, CNN Money, 27 Mar. 2025

Word History

Etymology

Latin cretaceus resembling chalk, from creta chalk

First Known Use

1832, in the meaning defined above

Rhymes for Cretaceous

• arenaceous
• argillaceous
• carbonaceous
• contumacious
• coriaceous
• efficacious
• farinaceous
• foliaceous
• membranaceous
• ochraceous
• olivaceous
• ostentatious

Kids Definition

Cretaceous

adjective

Cre·​ta·​ceous kri-ˈtā-shəs 

: of, relating to, or being the last period of the Mesozoic era of geological history marked by the extinction of the dinosaurs at the close of the period

also : relating to the corresponding system of rocks see geologic time

Cretaceous noun