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