/ Dictionary / Index T thioaldehyde: Meaning and Definition of Find definitions for: thi•o•al•de•hyde Pronunciation: (thī"ō-al'du-hīd"), [key] — n. Chem. any of a class of compounds formed by the action of hydrogen sulfide on aldehydes, and regarded as aldehydes with the oxygen replaced by sulfur. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. thio acid thioallyl ether Related Content Daily Word Quiz: denizen Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language