/ Dictionary / Index P presumption of fact: Meaning and Definition of Find definitions for: presump'tion of fact' Pronunciation: [key] — Law. Law. a presumption based on experience or knowledge of the relationship between a known fact and a fact inferred from it. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. presumption presumption of innocence Related Content Daily Word Quiz: gregarious Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language