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

Its descendants grew increasingly larger and became true tyrannosaurs, the dominant predators in North America in the late Cretaceous period. —Sara Hashemi, Smithsonian Magazine, 13 June 2025

For guide Tim Parrish, introducing anglers from across the country to these Cretaceous leftovers is a labor of love. —Chris Dorsey, Forbes.com, 9 June 2025

Researchers analyzed more than 50 avian fossils unearthed in northern Alaska—including bones from embryos and hatchlings—and found evidence that birds have been nesting at Arctic latitudes since at least 73 million years ago, during the Cretaceous period. —Sara Hashemi, Smithsonian Magazine, 2 June 2025

Sifting bones and teeth from the sediment of Alaska’s Prince Creek Formation, the authors identified an assortment of Cretaceous fossils and fossil fragments, which resembled the remains of modern gulls, geese, ducks, and loons. —Sam Walters, Discover Magazine, 29 May 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