"characterized by swelling in the groin," by 1795, from Latin bubo (genitive bubonis) "swelling of lymph glands" (in the groin), from Greek boubon "the groin; swelling in the groin" (which is of unknown origin) + -ic. Bubonic plague attested by 1827.
bubonic plague
bubble
bubble-gum
bubbly
bubby
bubo
bubonic
buccal
buccaneer
Bucephalus
buck
buckaroo