atomic mass

== English == === Noun === atomic mass (countable and uncountable, plural atomic masses) The mass of an atom. (proscribed) atomic weight; the average mass of atoms of an element. ==== Usage notes ==== Atomic mass may be measured in absolute terms, or, commonly, as a sum of the number of protons and neutrons in the nucleus. ==== Derived terms ==== ==== Related terms ==== ==== Translations ==== === See also ===