ul·cer 
(ŭlsər)
(ŭlsər)n.
1. A lesion of the skin or a mucous membrane such as the one lining the stomach or duodenum that is accompanied by formation of pus and necrosis of surrounding tissue, usually resulting from inflammation or ischemia.
2. A corrupting condition or influence.
[Middle English, from Old French ulcere, from Latin ulcus, ulcer-.]