Dictionary
mass number
noun
Definition of MASS NUMBER
: an integer that approximates the mass of an isotope and designates the number of nucleons in the nucleus
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First Known Use of MASS NUMBER
1923
Medical Dictionary
mass number
noun
Medical Definition of MASS NUMBER
: an integer that approximates the mass of an isotope and that designates the number of nucleons in the nucleus <the symbol for carbon of mass number 14 is 14C or C14>—compare atomic mass
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