/ Dictionary / Index S spatial summation: Meaning and Definition of Find definitions for: spa'tial summa'tion. Pronunciation: [key] See under(def. 5). Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. spatial spatiography Related Content Daily Word Quiz: ablution Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language