(pathology) 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.

(pathology) The most common form of active tuberculosis (TB) infecting the lungs, generally caused by Mycobacterium tuberculosis.

(pathology) A form of tuberculosis that is characterized by a wide dissemination into the human body and by the tiny size of the lesions (1-5 mm).