NCI Dictionary of Cancer Terms
The NCI Dictionary of Cancer Terms features 7,780 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 (seh-DAY-shun)
- A state of calmness, relaxation, or sleepiness caused by certain drugs. Sedation may be used to help relieve anxiety during medical or surgical procedures or to help cope with very stressful events. Drugs that relieve pain may be used at the same time.