asthmaleft: inflamed bronchial tube with contracted muscles and mucus dischargeright: normal bronchial tubeasth·ma (?z?m?, ?s?-)n. A chronic inflammatory disease of the lungs characterized by a narrowing of the airways and attacks of wheezing, coughing, and shortness of breath that are induced by triggers such as allergens, exercise, infections, and stress.[Middle English asma, from Medieval Latin, from Greek asthma.]asth·mat?ic (-m?t??k) adj. & n.asth·mat?i·cal·ly adv.American Heritage® Dictionary of the English Language, Fifth Edition. Copyright © 2016 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.asthma (?æsm?) n (Pathology) a respiratory disorder, often of allergic origin, characterized by difficulty in breathing, wheezing, and a sense of constriction in the chest[C14: from Greek: laborious breathing, from azein to breathe hard]Collins English Dictionary ? Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014asth?ma (?æz m?, ?æs-) n. a paroxysmal, often allergic disorder of respiration characterized by bronchospasm, wheezing, and difficulty in expiration. Also called bronchial asthma. [1350?1400; Middle English asma