/ Dictionary / Index S Say's law: Meaning and Definition of Find definitions for: Say's' law' Pronunciation: (sāz), [key] the principle, propounded by Jean Baptiste Say, that the supply of goods is always matched by the demand for them. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. says say-so Related Content Daily Word Quiz: pugilist Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language