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extrusive

[ik-stroo-siv, -ziv]
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adjective
  1. tending to extrude.
  2. pertaining to extrusion.
  3. Also effusive. Geology. noting or pertaining to a class of igneous rocks that have been forced out in a molten or plastic condition upon the surface of the earth.
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Origin of extrusive

First recorded in 1810–20; extrus(ion) + -ive
Related formsnon·ex·tru·sive, adjective
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018


Examples from the Web for extrusive

Historical Examples

  • Deposits formed at shallow depths are related to extrusive rocks and to intrusives near the surface.

    The Economic Aspect of Geology

    C. K. Leith


British Dictionary definitions for extrusive

extrusive

adjective
  1. tending to extrude
  2. (of igneous rocks) formed from magma issuing from volcanoes or cracks in the earth's crust; volcanicCompare intrusive (def. 2)
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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 extrusive

adj.

1816, from Latin extrusus, past participle of extrudere (see extrusion) + -ive. Related: Extrusively.

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Online Etymology Dictionary, © 2010 Douglas Harper