filvsfmWhat's the difference?

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

Which to use

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

#1,263
“fil” frequency rank
#9,661
“fm” frequency rank
10924
confusion score

Side-by-Side Comparison

Feature fil fm
Definition Petite partie longue et déliée qu’on détache de l’écorce du chanvre, du lin, etc. Symbole du fathom (la brasse en français), unité de mesure de profondeur hydrographique.

Where the eye mixes fil and fm

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

3 ch
fil
2 ch
fm

Look-alike desk: fil vs fm

These two trip readers on the page rather than in the ear: fil is \fil\ while fm is \ˈfæð.əm\. 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 (noun vs symbol), which is usually the fastest check. Our composite confusion score for this pair is 10924, derived from the frequency rank of both members and their visual similarity.

fil is recorded at frequency rank #1,263, classified as anoun, pronounced \fil\. fm is at rank #9,661, tagged as asymbol, pronounced \ˈfæð.əm\.

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 10924, this pair ranks #411,145 of 440,172 scored French confusable pairs - a relatively easy-to-tell-apart pair.

Orthographic DNA of fil vs fm

Shared letters: f. Private to "fil": il. Private to "fm": m.

"fil" · 3 letters · shape CVC  ·  "fm" · 2 letters · shape CC

Frequently Asked Questions

Can "fil" and "fm" be used interchangeably?
No - they are not even the same part of speech. "fil" is a noun and "fm" a symbol, so a sentence built for one is usually ungrammatical with the other.
In ordinary French text, does "fil" or "fm" show up more?
"fil" is the more common of the two: it sits at frequency rank #1,263 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.

After this comparison

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

  • Full dictionary entry for "fil" with definition, IPA, and generated misspellings. Word entry
  • Full dictionary entry for "fm" - compare definitions side by side with the headword page. Word entry
  • This pair ranks #411,145 of 440,172 scored French confusable pairs in this corpus vintage. Corpus statistics
  • "fil" and "fm" also get mixed up with nearby pairs, the highest-scored neighbour is "Fee vs fm". Nearby pair

Confusion rank #411,145 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