/ Dictionary / Index S spontaneous combustion: Meaning and Definition of Find definitions for: sponta'neous combus'tion Pronunciation: [key] the ignition of a substance or body from the rapid oxidation of its own constituents without heat from any external source. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. spontaneous abortion spontaneous generation Related Content Daily Word Quiz: blanch Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language