Which to use
“run” is a verb and “rust” is a noun - they look or sound alike but fill different roles in a sentence.
- #309
- “run” frequency rank
- #10,604
- “rust” frequency rank
- 10913
- confusion score
Side-by-Side Comparison
| Feature | run | rust |
|---|---|---|
| Definition | To move swiftly. | The deteriorated state of iron or steel as a result of moisture and oxidation; it consists mostly of iron(III) oxide (ferric oxide) and iron(II) oxide (ferrous oxide). |
Where the eye mixes run and rust
Muted = shared; highlighted = the visual trap. They share 2 letters in sequence.
Visual trap between run and rust
These two trip readers on the page rather than in the ear: run is /ɹʌn/ while rust is /ɹʌst/. 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 (verb vs noun), which is usually the fastest check. Our composite confusion score for this pair is 10913, derived from the frequency rank of both members and their visual similarity.
run is recorded at frequency rank #309, classified as averb, pronounced /ɹʌn/. rust is at rank #10,604, tagged as anoun, pronounced /ɹʌst/.
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 10913, this pair ranks #489,857 of 530,003 scored English confusable pairs - a relatively easy-to-tell-apart pair.
Orthographic DNA of run vs rust
Shared letters: ru. Private to "run": n. Private to "rust": st.
"run" · 3 letters · shape CVC · "rust" · 4 letters · shape CVCC
Known mistypes of this pair
- rust ← rrust · rsut · russt · rustt · ruts · urst
Frequently Asked Questions
Is swapping "run" for "rust" ever safe?
Frequency check: "run" vs "rust" - which ranks higher?
What to do next
Pronunciation already separates them, if the page still looks alike, the dictionary links below settle it.
- Full dictionary entry for "run" 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 #489,857 of 530,003 scored English confusable pairs in this corpus vintage. Corpus statistics
- "run" and "rust" also get mixed up with nearby pairs, the highest-scored neighbour is "Rua 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 #489,857 of 530,003 scored English pairs, corpus vintage 2026-09-03, not spelling advice.