What does "mass number" mean?

The total number of protons and neutrons in an atomic nucleus. Symbol: A

What is a synonym for "mass number"?

Common synonyms include: nucleon number.

noun

noun ·Rare ·Advanced level

Noun

1
The total number of protons and neutrons in an atomic nucleus. Symbol: A physical
2
the sum of the number of neutrons and protons in an atomic nucleus wordnet

Ellipsis of atomic mass number.