/ Dictionary / Index A acetaldehyde: Meaning and Definition of Find definitions for: ac•et•al•de•hyde Pronunciation: (as"i-tal'du-hīd"), [key] — n. Chem. a volatile, colorless, water-soluble liquid, CHO, having a pungent, fruitlike odor: used chiefly in the silvering of mirrors and in organic synthesis. Also called Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: acetaldehyde (Thesaurus) acetal acetaldol Related Content Daily Word Quiz: careening Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language