/ Dictionary / Index D diquat: Meaning and Definition of Find definitions for: di•quat Pronunciation: (dī'kwot), [key] — n. a yellow crystalline substance, CHBrN, used as a selective postemergence herbicide to control weeds on noncrop land and for aquatic weed control. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. dipyridamole dir. Related Content Daily Word Quiz: agitated Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language