atomic weight vs. atomic mass

atomic weight vs. atomic mass: What's the difference?

Atomic weight and atomic mass both refer to measurements of atoms of elements that are based on 1/12 of the mass of an atom of the carbon 12 isotope. Atomic weight is the average weight of all naturally occurring isotopes of a given element (adjusted based on which ones are most common), while atomic mass is the mass of an atom of a given element.