ulc-, ulcer- +
(Latin: sore, sore spot, painful spot)
2. An area of tissue erosion, for example, of the skin or lining of the gastrointestinal (GI) tract.
Due to the erosion, an ulcer is concave. It is always depressed below the level of the surrounding tissue.
Ulcers have a variety of causes and on the skin are often a result of irritation, as with bedsores, and they may become infected and inflamed as they grow.3. A circumscribed inflammatory and often suppurating lesion on the skin or an internal mucous surface resulting in the necrosis of tissue.
4. A corrupting condition or influence.