The Collaborative International Dictionary of English v.0.48:

Bubo \Bu"bo\ (b[=u]"b[-o]), n.; pl. Buboes (-b[-o]z). [LL.
   bubo the groin, a swelling in the groin, Gr. boubw`n.] (Med.)
   An inflammation, with enlargement, of a lymphatic gland, esp.
   in the groin, as in syphilis.
   [1913 Webster]

WordNet (r) 3.0 (2006):

bubo
    n 1: a lymph node that is inflamed and swollen because of plague
         or gonorrhea or tuberculosis
    2: a genus of Strigidae [syn: Bubo, genus Bubo]