[ kri-tey-shuhs ]
/ krɪˈteɪ ʃəs /
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resembling or containing chalk.
(initial capital letter)Geology. 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.


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



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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


cre·ta·ceous·ly, adverbnon·cre·ta·ceous, adjectivepost·cre·ta·ceous, adjectivesu·per·cre·ta·ceous, adjective
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2021

Example sentences from the Web for cretaceous

British Dictionary definitions for cretaceous (1 of 2)

/ (krɪˈteɪʃəs) /


consisting of or resembling chalk

Derived forms of cretaceous

cretaceously, adverb

Word Origin for cretaceous

C17: from Latin crētāceus, from crēta, literally: Cretan earth, that is, chalk

British Dictionary definitions for cretaceous (2 of 2)

/ (krɪˈteɪʃəs) /


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


the Cretaceous the Cretaceous period or rock system
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Scientific definitions for cretaceous

[ krĭ-tāshəs ]

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. See Chart at geologic time.
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.