/ Dictionary / Index M matter of law: Meaning and Definition of Find definitions for: mat'ter of law' Pronunciation: [key] an issue or matter to be determined according to the relevant principles of law. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. matter of fact matter of record Related Content Daily Word Quiz: abyss Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language