bu·bo 
(bbō, by-)
(bbō, by-)n. pl. bu·boes
An inflamed, tender swelling of a lymph node, especially in the area of the armpit or groin, that is characteristic of certain infectious diseases, such as bubonic plague, tuberculosis, and syphilis.
[Middle English, from Late Latin būbō, būbōn-, from Greek boubōn, groin, swelling.]