/ Dictionary / Index P probability theory: Meaning and Definition of Find definitions for: probabil'ity the"ory Pronunciation: [key] — Math., Statistics. Math.,Statistics. the theory of analyzing and making statements concerning the probability of the occurrence of uncertain events. Cf.(def. 4). Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. probability distribution probable 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