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

According to London's Natural History Museum, the Iguanodon was a herbivorous dinosaur that averaged about 32 feet in length and roamed in the Early Cretaceous period (110 million to 140 million years ago), primarily in Belgium and the United Kingdom. —Erin Clack, People.com, 15 Feb. 2025

Although one feature resembles that of other Cretaceous birds, the poor preservation and lack of bones kept the researchers from classifying it as a new species. —Paul Smaglik, Discover Magazine, 12 Feb. 2025

Sixty-six million years ago, a marine creature, minding its own business at the bottom of a Cretaceous sea, munched on some sea lilies—then didn’t feel too great. —Margherita Bassi, Smithsonian Magazine, 30 Jan. 2025

The species lived 76 million years ago during the Cretaceous period. —Irene Wright, Miami Herald, 23 Jan. 2025

Word History

Etymology

Latin cretaceus resembling chalk, from creta chalk

First Known Use

1832, in the meaning defined above

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