1. of, containing, or having the nature of, fire; fiery
Webster’s New World College Dictionary, Fourth Edition, compiled by the
editors of Webster’s New World Dictionaries. Copyright © 2010 by Houghton
Mifflin Harcourt. Published by Houghton Mifflin Harcourt. All rights reserved.
Word origin of 'igneous'L igneus < ignis, a fire < IE base *egnis > Sans agníḥ, fire, Lith ugnìs