An infectious disease of humans and animals caused by a species of mycobacterium, usually Mycobacterium tuberculosis, mainly infecting the lungs where it causes tubercles characterized by the expectoration of mucus and sputum, fever, weight loss, and chest pain, and transmitted through inhalation or ingestion of bacteria

Named for the encapsulated colonies of Mycobacterium tuberculosis within the lungs in pulmonary tuberculosis, which can look like small tubers (tubercles) on gross pathology. The disease has existed throughout human experience and had other names for millennia before scientific medicine renamed it with a New Latin term in the mid-19th century (1840s); in English it was called consumption because of the wasting away that consumed health and seemed even to consume flesh in some cases (for example, causing fistulas and tissue breakdown)