NCI Dictionary of Cancer Terms
The NCI Dictionary of Cancer Terms features 7,790 terms related to cancer and medicine.
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- 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.