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• cretaceous
  cretaceous

  adjective

  resembling or containing chalk.
• Cretaceous
  Cretaceous

  adjective

  of, denoting, or formed in the last period of the Mesozoic era, between the Jurassic and Tertiary periods, lasting 80 million years during which chalk deposits were formed and flowering plants first appeared

cretaceous

American  

[kri-tey-shuhs] / krɪˈteɪ ʃəs /

adjective

1. resembling or containing chalk.

2. (initial capital letter) noting or pertaining to a period of the Mesozoic Era, from 140 million to 65 million years ago, characterized by the greatest development and subsequent extinction of dinosaurs and the advent of flowering plants and modern insects.

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noun

1. (initial capital letter) the Cretaceous Period or System.

cretaceous ¹ British  

/ krɪˈteɪʃəs /

adjective

1. consisting of or resembling chalk

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Cretaceous ² British  

/ krɪˈteɪʃəs /

adjective

1. of, denoting, or formed in the last period of the Mesozoic era, between the Jurassic and Tertiary periods, lasting 80 million years during which chalk deposits were formed and flowering plants first appeared

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noun

1. the Cretaceous period or rock system

Cretaceous Scientific  

/ krĭ-tā′shəs /

1. The third and last period of the Mesozoic Era, from about 144 to 65 million years ago. During this time the supercontinent Pangaea continued to split up, with modern-day South America and Africa splitting apart, the Atlantic Ocean widening, and India disconnecting itself entirely from the other landmasses to which it was attached. Dinosaurs continued to be the dominant terrestrial animals, but many insect groups, modern mammals and birds, and the angiosperms (flowering plants) also first appeared. The Cretaceous Period ended with a mass extinction event in which about 75 percent of all species, including marine, freshwater, and terrestrial organisms, became extinct.

2. See Chart at geologic time

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Other Word Forms

• noncretaceous
  adjective
• postcretaceous
  adjective
• supercretaceous
  adjective
• cretaceously
  adverb

Etymology

Origin of cretaceous

1665–70; < Latin crētāceus, equivalent to crēt ( a ) chalk, clay ( cf. crayon) + -āceus -aceous; the geological period was defined from the chalk beds of SE England and associated formations

Example Sentences

See Examples For:

cretaceous Cretaceous

Earliest known mammalian stapes from an early cretaceous eutriconodontan mammal and implications for evolution of mammalian middle ear.

From Nature ● Nov. 12, 2017

Five miles below sea level, and beneath a shifting layer of cretaceous salt deposits, the discoveries have been estimated at 50 billion to 100 billion barrels.

From BusinessWeek ● May 10, 2012

Princeton paleontologists under the leadership of Dr. Glenn L. Jepsen. digging in a cretaceous formation near Red Lodge in southern Montana, found some old broken eggs.

From Time Magazine Archive

It is not until Paris has been left behind that the river begins to wash the bold white ramparts of the cretaceous beds.

From France by Home, Gordon Cochrane

Anthracites of newer, tertiary or cretaceous age, are found in the Crow’s Nest part of the Rocky Mountains in Canada, and at various points in the Andes in Peru.

From Encyclopaedia Britannica, 11th Edition, Volume 2, Slice 2 "Anjar" to "Apollo" by Various

This dinosaur would have lived 82 million years ago during the Late Cretaceous Period when Antarctica was very different from how it is today.

From BBC ● Jun. 29, 2026

"The site where Kank was discovered has provided extensive information about the Late Cretaceous environment of southern Patagonia, so continuing excavations there is crucial," explains Dr. Motta.

From Science Daily ● May 29, 2026

"During the Late Cretaceous, atmospheric CO2 levels reached about 1,000 parts per million -- comparable to projections for the end of this century," says Prof. Michael Wagreich, a paleoclimatologist at the University of Vienna.

From Science Daily ● May 27, 2026

Close behind was Tyrannotitan, another enormous theropod that lived in what is now Argentina more than 30 million years before T. rex during the Early Cretaceous period.

From Science Daily ● May 20, 2026

Ma glances at the lush tropical landscape and concludes, “This must be the Mesozoic era. Jurassic or Cretaceous period, I’d say, judging from the flora and fauna. What do you think, Jax?”

From "Dragons in a Bag" by Zetta Elliott