/ Dictionary / Index C critical region: Meaning and Definition of Find definitions for: crit'ical re'gion Pronunciation: [key] — Statistics. Statistics. the rejection region for the null hypothesis in the testing of a hypothesis. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. critical ratio critical state Related Content Daily Word Quiz: immense Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language