/ Dictionary / Index T TDN: Meaning and Definition of Find definitions for: TDN Pronunciation: [key] totally digestible nutrients. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. t distribution TDRS Related Content Daily Word Quiz: morose Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language