ratvsrustWhich spelling fits?

Which to use

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

#8,021
“rat” frequency rank
#37,050
“rust” frequency rank
45071
confusion score

Side-by-Side Comparison

Feature rat rust
Definition Rongeur à museau pointu, à pattes courtes et à queue longue, qui ronge et mange les grains, la paille, etc. Rouille.

Where the eye mixes rat and rust

Muted = shared; highlighted = the visual trap. They share 2 letters in sequence.

3 ch
rat
4 ch
rust

Why the eye confuses rat with rust

A purely visual mix-up. rat (\ʁa\) and rust (\ɻʌst\) 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 1 letter(s) in length. Our composite confusion score for this pair is 45071, derived from the frequency rank of both members and their visual similarity.

rat is recorded at frequency rank #8,021, classified as anoun, pronounced \ʁa\. rust is at rank #37,050, tagged as anoun, pronounced \ɻʌst\.

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 45071, this pair ranks #205,636 of 440,172 scored French confusable pairs - roughly mid-pack for confusability.

Orthographic DNA of rat vs rust

Shared letters: rt. Private to "rat": a. Private to "rust": su.

"rat" · 3 letters · shape CVC  ·  "rust" · 4 letters · shape CVCC

Known mistypes of this pair

  • rustrrust · rsut · russt · rustt · ruts · urst

Frequently Asked Questions

Can "rat" and "rust" be used interchangeably?
No. They are said differently (\ʁa\ versus \ɻʌst\) and carry different meanings; reading the sentence aloud is usually enough to catch the wrong one.
Which is more common, "rat" or "rust"?
"rat" is the more common of the two: it sits at frequency rank #8,021 in our French list, against #37,050 for "rust". The two are close in frequency, so neither is a safe default; check the meaning rather than guessing.

Useful next steps

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

  • Full dictionary entry for "rat" with definition, IPA, and generated misspellings. Word entry
  • Full dictionary entry for "rust" - compare definitions side by side with the headword page. Word entry
  • This pair ranks #205,636 of 440,172 scored French confusable pairs in this corpus vintage. Corpus statistics
  • "rat" and "rust" also get mixed up with nearby pairs, the highest-scored neighbour is "rouet vs rust". Nearby pair
  • Recorded mistypes exist for at least one side of this pair, useful when a spell-checker or OCR lands on the wrong form. See mistypes

Confusion rank #205,636 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