MSR

noun

"msr" is a 3-letter English headword indexed on PlainSpell.

The verdict

“MSR” is an uncommon English word, ranked #58,217 in English word frequency and used as a noun.

#58,217
frequency rank, English
3
letters

According to Wiktionary data (CC BY-SA, analyzed May 6, 2026) - Initialism of molten salt reactor.

Key facts for MSR
PropertyValue
HeadwordMSR
LanguageEnglish
Part of speechNoun
Letters3
Frequency rank#58,217
Misspellings tracked0
Confusable pairs0
SourceWiktionary (kaikki.org)

Where “MSR” sits in English frequency

Every-word frequency runs from the handful of words we use constantly (left) to the long tail used once in a blue moon (right). MSR lands here:

#1#100#1K#10K#100K
← used constantlyrarely used →

Scale is logarithmic (each tick is 10× rarer). Source: FrequencyWords open word-frequency list.

Spelling & Dictionary Insight

The English entry for MSR is 3 letters long, classified as a noun. Corpus data places it at rank #58,217 in overall English word frequency, marking it as uncommon enough that many writers pause before typing it. Wiktionary records 4 distinct senses for this headword, so context determines which meaning a reader should apply.

Zero misspellings are on record for MSR in our index, suggesting the orthography follows predictable English patterns. Our confusable-pair dataset has no match for it, suggesting its spelling stands apart enough that readers rarely confuse it with something else.

No documented word history exists for this headword, so its spelling is easiest to reason about phoneme by phoneme, absent a documented history. The correct English form is MSR, spelled M-S-R.

Definition

  1. 1
    Initialism of molten salt reactor.
  2. 2
    Initialism of Mars Sample Return mission.
  3. 3
    Mulder/Scully romance; a fanfic involving a romantic relationship between the characters Fox Mulder and Dana Scully of the The X-Files.
  4. 4
    Such fan fiction collectively.

Definitions, pronunciation, and etymology for this entry are drawn from Wiktionary via the kaikki.org structured extract (CC BY-SA); frequency ordering uses the FrequencyWords open word-frequency list (2018 English corpus, MIT). See the methodology for how each field is sourced and updated.

Frequently Asked Questions

How do you spell "MSR"?
"MSR" is spelled M-S-R.
What does "MSR" mean?
As a noun, "MSR" means: Initialism of molten salt reactor.
What language does "MSR" come from?
"MSR" is a English word. You can look up definitions, pronunciations, and spelling data for this and other words across English, Spanish, Portuguese, French, and German on PlainSpell.
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 “MSR”

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

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