/ Dictionary / Index P prodrug: Meaning and Definition of Find definitions for: pro•drug Pronunciation: (prō'drug"), [key] — n. Pharm. an inactive substance that is converted to a drug within the body by the action of enzymes or other chemicals. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. prodrome produce Related Content Daily Word Quiz: cygnet Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language