/ Dictionary / Index S substratosphere: Meaning and Definition of Find definitions for: sub•strat•o•sphere Pronunciation: (sub-strat'u-sfēr"), [key] — n. the upper troposphere. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. substrate substratum Related Content Daily Word Quiz: paradox Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language