amu
/ˈæmjuː/
noun
- A unit of mass used to measure atoms and molecules, equal to one twelfth of the mass of a carbon-12 atom.
- Chemists use amu to express the mass of individual atoms.
- One amu is approximately 1.66 × 10⁻²⁷ kilograms.
- The mass of a proton is about 1.007 amu.