/ Dictionary / Index D double decomposition: Meaning and Definition of Find definitions for: dou'ble decomposi'tion Pronunciation: [key] — Chem. Chem. a reaction whose result is the interchange of two parts of two substances to form two new substances, as AgNO + NaCl → AgCl + NaNO. Also called Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. double-decker double demy Related Content Daily Word Quiz: divulge Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language