NCI Dictionary of Cancer Terms
The NCI Dictionary of Cancer Terms features 8,235 terms related to cancer and medicine.
We offer a widget that you can add to your website to let users look up cancer-related terms. Get NCI’s Dictionary of Cancer Terms Widget.
- molecular mass
- listen (muh-LEH-kyoo-ler mas)
- The sum of the atomic masses of all atoms in a molecule, based on a scale in which the atomic masses of hydrogen, carbon, nitrogen, and oxygen are 1, 12, 14, and 16, respectively. For example, the molecular mass of water, which has two atoms of hydrogen and one atom of oxygen, is 18 (i.e., 2 + 16). Also called molecular weight.