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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

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

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

"Our findings suggest that the earliest octopuses were gigantic predators that occupied the top of the marine food chain in the Cretaceous," says Professor Yasuhiro Iba of Hokkaido University.

From Science Daily • Apr. 25, 2026

Using high-resolution grinding tomography along with an artificial intelligence model, the team discovered fossil jaws embedded within rock samples dating from the Late Cretaceous period, between 100 and 72 million years ago.

From Science Daily • Apr. 25, 2026

The presence of early Cretaceous dinosaur tracks in both the Robberg Formation and the Brenton Formation suggests that more sites may still be waiting to be found.

From Science Daily • Apr. 24, 2026

These areas contain limited deposits from the Cretaceous.

From Science Daily • Apr. 24, 2026

“They lived from the late Triassic to the Cretaceous period, though technically they’re not dinosaurs,” Kavita says in a know-it-all sort of way.

From "Dragons in a Bag" by Zetta Elliott