/ Dictionary / Index M miasma: Meaning and Definition of Find definitions for: mi•as•ma Pronunciation: (mī-az'mu, mē-), [key] — pl. -mas, -ma•ta noxious exhalations from putrescent organic matter; poisonous effluvia or germs polluting the atmosphere. a dangerous, foreboding, or deathlike influence or atmosphere. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: miasma (Thesaurus) Miaskovsky Miass Related Content Daily Word Quiz: cautious Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language