NCI Dictionary of Cancer Terms
The NCI Dictionary of Cancer Terms features 7,790 terms related to cancer and medicine.
Browse the dictionary by selecting a letter of the alphabet or by entering a cancer-related word or phrase in the search box.
- listen (UL-seh-RAY-shun)
- The formation of a break on the skin or on the surface of an organ. An ulcer forms when the surface cells die and are cast off. Ulcers may be associated with cancer and other diseases.