/ Dictionary / Index M mercaptan: Meaning and Definition of Find definitions for: mer•cap•tan Pronunciation: (mur-kap'tan), [key] — n. Chem. any of a class of sulfur-containing compounds having the type formula RSH, in which R represents a radical, and having an extremely offensive, garlicky odor. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. mercantilism mercaptide 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