Phrase guide

mass number

noun · 2 senses · updated from the 2026-07-25 local source snapshot

Definitions and examples are grouped by meaning. Pronunciation, history, word forms, translations, descendants, synonyms, antonyms, derived terms, and related words appear whenever the source provides them.

Sound

Pronunciation

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1

noun

Meaning 1

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

Definition source: English Wiktionary via Wiktextract

Usage: physical

Topics: chemistry, natural-sciences, physical-sciences, physics

No example sentence was provided for this meaning.

Meaning relationships

Synonyms: none provided

Antonyms: none provided

2

noun

Meaning 2

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

Definition source: Princeton WordNet 3.0

No example sentence was provided for this meaning.

Meaning relationships

Synonyms: nucleon number

Antonyms: none provided

Broader terms: mass unit

History

Etymology

Ellipsis of atomic mass number.

Across languages

Translations

27 source translations are retained for this English entry.

  • Arabic: عَدَد كُتْلِيّ (ʕadad kutliyy) — number of protons and neutrons in an atomic nucleus
  • Bulgarian: масово число (masovo čislo) — number of protons and neutrons in an atomic nucleus
  • Catalan: nombre màssic — number of protons and neutrons in an atomic nucleus
  • Catalan: nombre de massa — number of protons and neutrons in an atomic nucleus
  • Chinese Mandarin: 質量數 /质量数 (zhìliàngshù) — number of protons and neutrons in an atomic nucleus
  • Danish: nukleontal — number of protons and neutrons in an atomic nucleus
  • Dutch: massagetal — number of protons and neutrons in an atomic nucleus
  • Finnish: massaluku — number of protons and neutrons in an atomic nucleus
  • French: nombre de masse — number of protons and neutrons in an atomic nucleus
  • Georgian: მასური რიცხვი (masuri ricxvi) — number of protons and neutrons in an atomic nucleus
  • German: Massenzahl — number of protons and neutrons in an atomic nucleus
  • Greek: μαζικός αριθμός (mazikós arithmós) — number of protons and neutrons in an atomic nucleus
  • Hungarian: tömegszám — number of protons and neutrons in an atomic nucleus
  • Indonesian: nomor massa — number of protons and neutrons in an atomic nucleus
  • Italian: numero di massa — number of protons and neutrons in an atomic nucleus
  • Korean: 질량수 (jillyangsu) — number of protons and neutrons in an atomic nucleus
  • Latvian: masas skaitlis — number of protons and neutrons in an atomic nucleus
  • Māori: tau karihi — number of protons and neutrons in an atomic nucleus
  • Polish: liczba masowa — number of protons and neutrons in an atomic nucleus
  • Portuguese: número de massa — number of protons and neutrons in an atomic nucleus
  • Russian: массовое число́ (massovoje čisló) — number of protons and neutrons in an atomic nucleus
  • Spanish: número másico — number of protons and neutrons in an atomic nucleus
  • Spanish: número de masa — number of protons and neutrons in an atomic nucleus
  • Swedish: masstal — number of protons and neutrons in an atomic nucleus
  • Thai: เลขมวล — number of protons and neutrons in an atomic nucleus
  • Ukrainian: ма́сове число́ (másove čysló) — number of protons and neutrons in an atomic nucleus
  • Vietnamese: số khối — number of protons and neutrons in an atomic nucleus