NCI Dictionary of Cancer Terms
The NCI Dictionary of Cancer Terms features 7,881 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 (eh-PEN-dih-muh)
- A thin membrane that lines the fluid-filled spaces in the brain and spinal cord. It is made up of a type of glial cell called an ependymal cell.