• synonyms


  1. noting or pertaining to a period of the Mesozoic Era, occurring from 230 to 190 million years ago and characterized by the advent of dinosaurs and coniferous forests.
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  1. Also Tri·as [trahy-uh s] /ˈtraɪ əs/ the Triassic Period or System.
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Origin of Triassic

1835–45; Trias the three-part series of strata characterizing the period (< German < Greek triás; see triad) + -ic
Related formspost-Tri·as·sic, adjective
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018

Examples from the Web for triassic

Historical Examples of triassic

  • No sir, not one, and I can find no sign of the Triassic period.

    Punchinello, Vol. 1. No. 20, August 13, 1870


  • Now my theory is, you 're in strata here of what we call the Triassic Age.

  • It is further agreed that the Triassic strata were deposited after these.

    Mr. Gladstone and Genesis

    Thomas Henry Huxley

  • From Prototheria to something like the Theromorpha at the bottom of the Triassic strata.

    The Last Link

    Ernst Haeckel

  • The primitive-looking Notidani do not appear before the Triassic.

British Dictionary definitions for triassic


  1. of, denoting, or formed in the first period of the Mesozoic era that lasted for 42 million years and during which reptiles flourished
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  1. the Triassic or Trias the Triassic period or rock system
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Word Origin for Triassic

C19: from Latin trias triad, with reference to the three subdivisions
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 triassic



1841, from German, coined 1841 by German geologist Friedrich August von Alberti (1795-1878), from Greek trias "triad" (see triad), because it is divisible (in Germany) into three groups.

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Online Etymology Dictionary, © 2010 Douglas Harper

triassic in Science


  1. The earliest period of the Mesozoic Era, from about 245 to 208 million years ago. During the early part of the Triassic Period the supercontinent Pangaea was located along the equator; by the end of the Triassic it had started to split up. Land life diversified in the Triassic in response to the mass extinctions of the end of the Paleozoic. Conifers, cycads, marine reptiles, dinosaurs, and the earliest mammals first appeared. See Chart at geologic time.
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The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.