tu·ber·cu·lo·sis (to?o-bûr?ky?-l??s?s, tyo?o-)n. Abbr. TB1. An infectious disease of humans and animals caused by the tubercle bacillus and characterized by the formation of tubercles on the lungs and other tissues of the body, often developing long after the initial infection.2. Tuberculosis of the lungs, characterized by the coughing up of mucus and sputum, fever, weight loss, and chest pain.[Latin t?berculum, tubercle; see tubercle + -osis.]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.tuberculosis (tj??b??kj??l??s?s) n (Pathology) a communicable disease caused by infection with the tubercle bacillus, most frequently affecting the lungs (pulmonary tuberculosis). Also called: consumption or phthisis Abbreviation: TB [C19: from New Latin; see tubercle, -osis]Collins English Dictionary ? Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014tu?ber?cu?lo?sis (t??b?r ky??lo? s?s, ty?-) n. 1. an infectious disease that may affect almost any tissue of the body, esp. the lungs, caused by the organism Mycobacterium tuberculosis, and characterized by tubercles. 2. this disease when affecting the lungs. Abbr.: TB [1855?60;