noun

1. an open sore (other than a wound) on the skin or some mucous membrane, as the lining of the stomach (peptic ulcer), characterized by the disintegration of the tissue and, often, the discharge of pus
2. any corrupting or festering condition or influence

Etymology: L ulcus (gen. ulceris) < IE *elkos-, abscess > Sans árśas-, hemorrhoids, Gr helkos, abscess, wound