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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

in the meaning defined above

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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

Learn More about mass number

  1. Britannica.com: Encyclopedia article about mass number

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