MSR

noun

By · According to Wiktionary data (CC BY-SA) ·

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

The verdict

“MSR” is uncommon English (frequency #58,217 among 4,057 “M” headwords), classed as a noun. The kind of spelling people second-guess.

#58,217
frequency rank, English
4,057
“M” headwords

According to Wiktionary data (CC BY-SA, analyzed September 3, 2026) - Initialism of molten salt reactor.

Corpus desk

Index EN-msr · MSR · English

MSR · rank #58,217 · 0 variants · 0 confusables

  • FREQ-RARE #58,217
  • LEN-MID 3 letters
  • VOW-0 0 vowels
  • CONFUS-0 No pairs
  • VAR-0 0 variants
  • BOOK-MID 4,057
  • PHOTO-FINISH Muirhead

Nearest frequency peer: Muirhead (+1 rank slots)

Read with this headword: Spelling guide for this pattern

Desk codes from Wiktionary headword shape, FrequencyWords rank tier, confusable-pair count, generated misspelling depth, letter-cohort book size, and photo-finish peer. Not a difficulty grade.

Long-tail ranks near “MSR”

Sparse band: bars invert rank so rarer forms read shorter

corpus weight

What this shows Long-tail view: where “MSR” sits against similarly uncommon English ranks.

Source FrequencyWords open word-frequency list As of September 3, 2026
Key facts for MSR
PropertyValue
HeadwordMSR
LanguageEnglish
Part of speechNoun
Letters3
Frequency rank#58,217
Misspellings tracked0
Confusable pairs0
SourceWiktionary (kaikki.org)

Long-tail rank of “MSR” in English

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

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

Ticks step logarithmically, so each one marks a roughly tenfold drop in how often the word turns up. Rare peers in the same band: “Muirhead” (#58,218), “multicolor” (#58,219), “moos” (#58,213). Among 4,057 “M” headwords, “MSR” is #58,217. Source: FrequencyWords open word-frequency list.

Rare enough to double-check

MSR is uncommon English at frequency #58,217 among 4,057 “M” headwords, classed as anoun. Rarity is why readers land here mid-draft. 4 senses are on record.

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.

Recorded use

Wiktionary examples

These source excerpts show how MSR appears in context. They illustrate usage; the definition above remains the entry’s reference meaning.

  1. Although I regard this as a romantic piece, it's not an MSR in the usual sense--our heroes don't ride off into the sunset locked in each other's arms.
  2. I'm writing an MSR (big surprise there) and I have a scene where M&S do a nice, sensuous slow dance.

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.

Similar English words by spelling shape

Same letter count and similar misspelling depth for "MSR", not the corpus desk frequency band.

Same letter count

Frequency-ranked English headwords with 3 letters (nearest by frequency rank).

Meo#58,195OIG#58,247PSB#58,298Pua#58,299

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

Source: FrequencyWords open word-frequency list