fmvsfoiWhich spelling fits?

Quick tell: fm is a symbol, foi is a noun, so they fill different roles in a sentence.

Which to use

“fm” is a symbol and “foi” is a noun - they look or sound alike but fill different roles in a sentence.

#9,661
“fm” frequency rank
#1,478
“foi” frequency rank
11139
confusion score

Side-by-Side Comparison

Feature fm foi
Definition Symbole du fathom (la brasse en français), unité de mesure de profondeur hydrographique. Croyance aux dogmes de la religion, en Dieu.

Where the eye mixes fm and foi

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

2 ch
fm
3 ch
foi

Visual trap between fm and foi

These two trip readers on the page rather than in the ear: fm is \ˈfæð.əm\ while foi is \fwa\. Spoken aloud the problem disappears. In writing it persists, because they differ by 1 letter(s) in length, and the parts of speech differ too (symbol vs noun), which is usually the fastest check. Our composite confusion score for this pair is 11139, derived from the frequency rank of both members and their visual similarity.

fm is recorded at frequency rank #9,661, classified as asymbol, pronounced \ˈfæð.əm\. foi is at rank #1,478, tagged as anoun, pronounced \fwa\.

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 11139, this pair ranks #410,307 of 440,172 scored French confusable pairs - a relatively easy-to-tell-apart pair.

Orthographic DNA of fm vs foi

Shared letters: f. Private to "fm": m. Private to "foi": io.

"fm" · 2 letters · shape CC  ·  "foi" · 3 letters · shape CVV

Frequently Asked Questions

Do "fm" and "foi" mean the same thing in a sentence?
No - they are not even the same part of speech. "fm" is a symbol and "foi" a noun, so a sentence built for one is usually ungrammatical with the other.
Frequency check: "fm" vs "foi" - which ranks higher?
"foi" is the more common of the two: it sits at frequency rank #1,478 in our French list, against #9,661 for "fm". The two are close in frequency, so neither is a safe default; check the meaning rather than guessing.

What to do next

Visual near-miss handled. Browse the word pages or a neighbour when the next look-alike shows up.

  • Full dictionary entry for "fm" with definition, IPA, and generated misspellings. Word entry
  • Full dictionary entry for "foi" - compare definitions side by side with the headword page. Word entry
  • This pair ranks #410,307 of 440,172 scored French confusable pairs in this corpus vintage. Corpus statistics
  • "fm" and "foi" also get mixed up with nearby pairs, the highest-scored neighbour is "Fee vs fm". Nearby pair

Confusion rank #410,307 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