mass number

noun

Detailed reference entry for the English word "mass-number", 11-letters, with pronunciation in International Phonetic Alphabet notation, etymology traced through Germanic and Romance roots where applicable, common misspelling variants catalogued from Wiktionary, and usage frequency ranked against an open word-frequency list covering the top 100,000 English words. PlainSpell covers English, Spanish, Portuguese, French, and German spelling with confusable-pair detection that highlights visually and phonetically similar words. This entry for "mass-number" includes synonyms, antonyms, homophones, and cross-language translation pointers sourced from Wiktionary via the kaikki.org extract. Whether you are verifying the correct spelling of "mass-number" for academic writing, checking homophone confusion, or exploring etymological origins, this page provides a citation-backed, free reference that requires no sign-up.

The verdict

“mass number” is outside the top-ranked English vocabulary, used as a noun - the kind of word writers most often double-check.

Unranked
below top-frequency English
11
letters

According to Wiktionary data (CC BY-SA, analyzed May 6, 2026) — The total number of protons and neutrons in an atomic nucleus. Symbol: A

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Key facts for mass number
PropertyValue
Headwordmass number
LanguageEnglish
Part of speechNoun
Letters11
Misspellings tracked0
Confusable pairs0
SourceWiktionary (kaikki.org)

Where “mass number” sits in English frequency

mass number falls outside the top-100,000 ranked English words, the long-tail zone of technical, archaic, or low-frequency vocabulary, exactly where readers second-guess spellings most.

Beyond rank #100,000. Source: FrequencyWords open word-frequency list.

Spelling & Dictionary Insight

The English entry for mass number is 11 letters long, classified as a noun. It sits outside the most-frequent rank tiers, which is often why uncommon words generate more spelling variants per reader. The dominant gloss from Wiktionary reads: "The total number of protons and neutrons in an atomic nucleus. Symbol: A".

No misspelling variants are generated for mass number in our index, suggesting the orthography follows predictable English patterns. It is not paired with a close-neighbour confusable in our dataset, which tends to mean the word is visually distinctive enough to stand on its own.

Etymologically, the entry records: Ellipsis of atomic mass number. Root origin matters for spelling because borrowed morphemes (Greek, Latin, Old French, Old English) carry their source-language orthographic conventions into modern English, which is why historical etymology is often the cleanest predictor of whether a cluster like "-ough", "-eau", or "-tion" will appear. For readers arriving here from a spelling check, the authoritative guidance is: the correct English form is mass number, spelled M-A-S-S- -N-U-M-B-E-R, and any other sequence of those letters, regardless of how natural it feels, is a misspelling in standard orthography.

Definition

  1. 1
    The total number of protons and neutrons in an atomic nucleus. Symbol: A

Etymology

Ellipsis of atomic mass number.

Synonyms

atomic mass numbernucleon number

This word in other languages

Definitions, pronunciation, and etymology for this entry are drawn from Wiktionary via the kaikki.org structured extract (CC BY-SA). See the methodology for how each field is sourced and updated.

Cite this page

Free to reuse with attribution (CC BY-SA). Copy the citation:

PlainSpell, “mass number, English word data” (May 6, 2026). Derived from Wiktionary (kaikki.org, CC BY-SA) and an open word-frequency list. https://plainspell.com/en/word/mass-number

Frequently Asked Questions

How do you spell "mass number"?
"mass number" is spelled M-A-S-S- -N-U-M-B-E-R.
What does "mass number" mean?
As a noun, "mass number" means: The total number of protons and neutrons in an atomic nucleus. Symbol: A
What is the origin of the word "mass number"?
Ellipsis of atomic mass number. See the full etymology section above for more details.
Is PlainSpell free to use?
Yes, PlainSpell is a completely free word reference. You can look up definitions, pronunciations, confusable pairs, homophones, and spelling corrections across 5 languages without any sign-up or subscription.

Using “mass number”

The practical upshot for anyone who landed here from a spell-check.

  • The one correct English spelling is M-A-S-S- -N-U-M-B-E-R - every other letter order is a misspelling in standard orthography.
  • Browse more English words and confusable pairs in the same reference. English words

Nearby English words

Other entries that begin with the letter M in our English index:

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Data Source: Wiktionary (via kaikki.org), licensed under CC BY-SA & GFDL. Word ordering uses an open word-frequency list; misspelling variants are generated by edit-distance from the correct headword.

Source: Wiktionary (via kaikki.org) Structured Wiktionary extract

Source: FrequencyWords open word-frequency list FrequencyWords open word-frequency list