emphysematop: normal bronchiole and alveolibottom: diseased bronchiole with mucus, enlarged air sacs in the alveoli, and fewer capillariesem·phy·se·ma (?m?f?-s??m?, -z??-)n.1. A pathological condition of the lungs marked by an abnormal increase in the size of the air spaces, resulting in labored breathing and an increased susceptibility to infection. It can be caused by irreversible expansion of the alveoli or by the destruction of alveolar walls.2. An abnormal distension of body tissues caused by retention of air.[Greek emph?s?ma, inflation, from emph?s?n, to blow in : en-, in; see en-2 + ph?s?n, to blow (from ph?sa, bellows, bladder).]em?phy·sem?a·tous (-s?m??-t?s, -s??m?-, -z?m??-, -z??m?-) adj.em?phy·se?mic adj. & n.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.emphysema (??mf??si?m?) n1. (Pathology) Also called: pulmonary emphysema a condition in which the air sacs of the lungs are grossly enlarged, causing breathlessness and wheezing2. (Pathology) the abnormal presence of air in a tissue or part[C17: from New Latin, from Greek emphus?ma, a swelling up, from emphusan to inflate, from phusan to blow] emphysematous adjCollins English Dictionary ? Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014em?phy?se?ma (??m f??si m?, -?zi-) n. 1. a chronic disease of the lungs characterized by difficulty in breathing due to abnormal enlargement and loss of elasticity of the air spaces. 2. any abnormal distention of an organ or part of the body with air or other gas. [1655?65;