/ Dictionary / Index S summative: Meaning and Definition of Find definitions for: sum•ma•tive Pronunciation: (sum'u-tiv), [key] — adj. additive. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: summative (Thesaurus) summation method summer 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