/ Dictionary / Index M megaloblast: Meaning and Definition of Find definitions for: meg•a•lo•blast Pronunciation: (meg'u-lu-blast"), [key] — n. Pathol. an abnormally large, immature, and dysfunctional red blood cell found in the blood of persons with pernicious anemia or certain other disorders. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: megaloblast (Thesaurus) megalo- megalocardia Related Content Daily Word Quiz: placid Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language