/ Dictionary / Index D diagnostics: Meaning and Definition of Find definitions for: di•ag•nos•tics Pronunciation: (dī'ug-nos'tiks), [key] — n. (used with a sing. v.) Med. the discipline or practice of diagnosis. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: diagnostics (Thesaurus) diagnostician diagonal Related Content Daily Word Quiz: soporific Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language