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  1. noting or pertaining to a period of the Mesozoic Epoch, occurring from 190 to 140 million years ago and characterized by an abundance of dinosaurs and the advent of birds and mammals.
  1. the Jurassic Period or System.

Origin of Jurassic

1825–35; Jur(a) + -assic, suffix extracted from Triassic; compare French jurassique
Related formspost-Ju·ras·sic, adjective
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018

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British Dictionary definitions for jurassic


  1. of, denoting, or formed in the second period of the Mesozoic era, between the Triassic and Cretaceous periods, lasting for 55 million years during which dinosaurs and ammonites flourished
  1. the Jurassic the Jurassic period or rock system

Word Origin

C19: from French jurassique, after the Jura (Mountains)
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

Word Origin and History for jurassic



in reference to "geological period between the Triassic and the Cretaceous," 1847, from French Jurassique, literally "of the Jura Mountains," between France and Switzerland, whose limestones were laid down during this geological period. Used in English in a literal sense "pertaining to the Jura Mountains" by 1831. The name is said to be from Gaulish *iuris "wooded mountain."

Online Etymology Dictionary, © 2010 Douglas Harper

jurassic in Science


  1. The second and middle period of the Mesozoic Era, from about 208 to 144 million years ago. During this time the supercontinent Pangaea continued to split up and numerous shallow seas inundated the new continents. Dinosaurs were the dominant form of terrestrial animal life, and the earliest birds appeared. Marine life was dominated by ammonites and belemnites, and sponges, corals, bryozoa, and gastropods all flourished. Gymnosperms and cycads were the dominant land plants. See Chart at geologic time.
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