NCI Dictionary of Cancer Terms
The NCI Dictionary of Cancer Terms features 7,812 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 (OK-sih-jen)
- A colorless, odorless gas. It is needed for animal and plant life. Oxygen that is breathed in enters the blood from the lungs and travels to the tissues.