/ Dictionary / Index A ADA deficiency: Meaning and Definition of Find definitions for: ADA deficiency. Pronunciation: [key] See Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. Adad adage Related Content Daily Word Quiz: blithesome Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language