/ Dictionary / Index T TDA: Meaning and Definition of Find definitions for: TDA Pronunciation: [key] tax-deferred annuity. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. TD TDD 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