M4vsmuWhich spelling fits?

Which to use

“M4” and “mu” are a confusable French pair: similar on the page, but distinct in meaning, check the gloss before you choose.

#39,888
“M4” frequency rank
#14,985
“mu” frequency rank
54873
confusion score

Side-by-Side Comparison

Feature M4 mu
Definition Messier 4, un amas globulaire. μ, Μ, douzième lettre et huitième consonne de l’alphabet grec.

Where the eye mixes M4 and mu

Muted = shared; highlighted = the visual trap. They share 1 letter in sequence.

2 ch
M4
2 ch
mu

Visual trap between M4 and mu

A purely visual mix-up. M4 (\ɛm katʁ\) and mu (\my\) are said differently, so reading them aloud is the quickest way to catch the wrong one. On the page they stay close: they differ by a single letter - 4 in “M4” becomes u in “mu”. Our composite confusion score for this pair is 54873, derived from the frequency rank of both members and their visual similarity.

M4 is recorded at frequency rank #39,888, classified as anoun, pronounced \ɛm katʁ\. mu is at rank #14,985, tagged as anoun, pronounced \my\.

Glosses for this pair are partially populated in our dataset, but the full side-by-side definitions above should still guide you to the right choice.

With a confusion score of 54873, this pair ranks #131,109 of 440,172 scored French confusable pairs - roughly mid-pack for confusability.

Orthographic DNA of M4 vs mu

Shared letters: m. Private to "M4": -. Private to "mu": u.

"M4" · 1 letters · shape C  ·  "mu" · 2 letters · shape CV

Frequently Asked Questions

Can "M4" and "mu" be used interchangeably?
No. They are said differently (\ɛm katʁ\ versus \my\) and carry different meanings; reading the sentence aloud is usually enough to catch the wrong one.
In ordinary French text, does "M4" or "mu" show up more?
"mu" is the more common of the two: it sits at frequency rank #14,985 in our French list, against #39,888 for "M4". The two are close in frequency, so neither is a safe default; check the meaning rather than guessing.

After this comparison

Eye-level mix-up between "M4" and "mu" is sorted above. Next: full entries or other pairs that share a letter shape.

  • Full dictionary entry for "M4" with definition, IPA, and generated misspellings. Word entry
  • Full dictionary entry for "mu" - compare definitions side by side with the headword page. Word entry
  • This pair ranks #131,109 of 440,172 scored French confusable pairs in this corpus vintage. Corpus statistics
  • "M4" and "mu" also get mixed up with nearby pairs, the highest-scored neighbour is "M4 vs MWh". Nearby pair

Confusion rank #131,109 of 440,172 scored French pairs, corpus vintage 2026-09-03, not spelling advice.

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

Source: FrequencyWords open word-frequency list