/ Dictionary / Index D decillion: Meaning and Definition of Find definitions for: de•cil•lion Pronunciation: (di-sil'yun), [key] — n. a cardinal number represented in the U.S. by 1 followed by 33 zeros, and in Great Britain by 1 followed by 60 zeros. —adj. amounting to one decillion in number. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. deciliter decimal Related Content Daily Word Quiz: philtrum Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language