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

Early Cretaceous deep-water bedforms west of the Guinea Plateau revise the opening history of the Equatorial Atlantic Gateway. —Soo Kim, MSNBC Newsweek, 8 May 2025

Before that period, during the Late Jurassic and Early Cretaceous, fierce aquatic reptilian predators prowled the oceans, including pliosaurids with jaws over six feet long, toothy thalattosuchia crocodyliforms, and fast, fish-like ichthyosaurians. —Paul Smaglik, Discover Magazine, 2 May 2025

The gigantic mosasaur lived at the end of the Cretaceous period, around 66 million years ago. —Sarah Kuta, Smithsonian Magazine, 29 Apr. 2025

Seeing a hell ant preserved in limestone so far away from Burma indicates that these ants were widely distributed and likely crossed Cretaceous landmasses several times. —Laura Baisas, Popular Science, 24 Apr. 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