English▸ noun an open sore on an external or internal surface of the body, caused by a break in the skin or mucous membrane which fails to heal. Ulcers range from small, painful sores in the mouth to bedsores and serious lesions of the stomach or intestine.
▪ a moral blemish or corrupting influence:
he's a conman with an incurable ulcer called gambling.
– ORIGIN late Middle English: from Latin ulcus, ulcer-.