/ Dictionary / Index D disproportionation: Meaning and Definition of Find definitions for: dis•pro•por•tion•a•tion Pronunciation: (dis"pru-pôr"shu-nā'shun, -pōr"-), [key] — n. Chem. the simultaneous oxidation and reduction of a substance reacting with itself, thereby forming two dissimilar molecules, as 2CH→CH+CH. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. disproportionate disprove Related Content Daily Word Quiz: agitated Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language