mass number

1. 1.

   the sum of the number of neutrons and protons in an atomic nucleus

   Synonymsnucleon number

   Broadermass unit

Questions about mass number

What does mass number mean?

mass number means "the sum of the number of neutrons and protons in an atomic nucleus".

What is another word for mass number?

Close synonyms include nucleon number. Each sense on this page lists its own synonyms, because a word with several meanings rarely has one substitute that works for all of them.

Is mass number a common word?

mass number is banded "Rare" — specialist or archaic — most readers will not have met it. The band comes from how often the word appears in a large corpus of everyday English, not from an editor's impression.