/ Dictionary / Index A adstratum: Meaning and Definition of Find definitions for: ad•stra•tum Pronunciation: (ad'strā"tum, -strat"um), [key] — pl. -stra•ta a substratum or superstratum. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. adst. feb. adsuki bean Related Content Daily Word Quiz: exemplary Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language