/ Dictionary / Index S significance level: Meaning and Definition of Find definitions for: signif'icance lev"el Pronunciation: [key] (in the statistical test of a hypothesis) the maximum probability of a Type I error for all distributions consistent with the null hypothesis. Also called Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. significance significancy Related Content Daily Word Quiz: neologism Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language