• synonyms


[ig-nee-uh s]
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  1. Geology. produced under conditions involving intense heat, as rocks of volcanic origin or rocks crystallized from molten magma.
  2. of, relating to, or characteristic of fire.
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Origin of igneous

1655–65; < Latin igneus, equivalent to ign(is) fire + -eus -eous
Related formsnon·ig·ne·ous, adjective
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018

Related Words


Examples from the Web for igneous

Historical Examples

  • Traces of it are found in practically all igneous and most sedimentary rocks.

    Commercial Geography

    Jacques W. Redway

  • The close association both in place and age with igneous rocks.

  • Igneous rocks are formed by the cooling of molten rock material.

  • They occur in limestones and shales and are not associated with igneous rocks.

  • These are characterized by igneous rocks of andesitic nature.

British Dictionary definitions for igneous


  1. (of rocks) derived by solidification of magma or molten lava emplaced on or below the earth's surfaceCompare sedimentary, metamorphic (def. 2)
  2. of or relating to fire
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Word Origin

C17: from Latin igneus fiery, from ignis fire
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 igneous


1660s, from Latin igneus "of fire, fiery," from ignis "fire," from PIE *egni- "fire" (cf. Sanskrit agnih "fire, sacrificial fire," Old Church Slavonic ogni, Lithuanian ugnis "fire").

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Online Etymology Dictionary, © 2010 Douglas Harper

igneous in Science


  1. Relating to rocks or minerals formed by the cooling and hardening of magma or molten lava. Basalt and granite are examples of igneous rocks.
  2. Relating to the processes, such as volcanism, by which such rocks and minerals form.
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The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.