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.
- International Unit
- listen (IN-ter-NA-shuh-nul YOO-nit)
- A unit used to measure the activity of many vitamins, hormones, enzymes, and drugs. An International Unit is the amount of a substance that has a certain biological effect. For each substance there is an international agreement on the biological effect that is expected for 1 International Unit. Also called IU.