mass number

noun

, Physics.

1. the integer nearest in value to the atomic weight of an atom and equal to the number of nucleons in the nucleus of the atom. : A

mass number

noun

1. the total number of neutrons and protons in the nucleus of a particular atom A Also callednucleon number

mass number

1. The total number of protons and neutrons in the nucleus of an atom. For example, nitrogen has 7 protons and 7 neutrons in its nucleus, giving it a mass number of 14. Isotopes of elements are distinguished by their mass number; for example, carbon-12 and carbon-14 have mass numbers of 12 and 14 respectively.
2. Also called nucleon number
3. Compare atomic mass

Word History and Origins

Origin of mass number¹

First recorded in 1920–25

Example Sentences

People were going out to vote in mass numbers to vote Barack in office.

From TruthBeTold.news

Now, people are voting in mass numbers to vote the current president out of office.

From TruthBeTold.news

There, you can donate to the cause and join the “mass number of Manson supporters worldwide.”

From The Daily Beast

In the black peaty mass Number 5, fragments of wood of the oak, yew, and fir have been recognised.

From Project Gutenberg