A medical term applied to a symptom or sign that is characteristic of a disease or disorder and is therefore sufficient to make a diagnosis.
A term applied to signs or symptoms which are especially characteristic of certain diseases, and on the presence or absence of which the diagnosis depends. Thus the discovery of the Mycobacterium tuberculosis in the sputum is said to be pathognomonic of pulmonary tuberculosis.
adj. describing a symptom or sign that is characteristic of or unique to a particular disease. The presence of such a sign or symptom allows positive diagnosis of the disease.
Health Encyclopedia