noun, noun which may take the genitive case particle 'no'
Medical term for a localized area of disease, such as a tumor, infection, or abnormal tissue. Used both as a noun and adjectivally with の.
A small lesion was found in the lung on the CT scan.
This medicine acts directly on the focus of the disease.
inflamed part; site of inflammation
Compound of 病 (disease) and 巣 (nest), literally 'disease nest'. The term is a calque from German 'Krankheitsherd' (focus of disease).