Which to use
“rigor” and “rigour” are a confusable English pair: similar on the page, but distinct in meaning, check the gloss before you choose.
- #26,577
- “rigor” frequency rank
- #43,349
- “rigour” frequency rank
- 69926
- confusion score
Side-by-Side Comparison
| Feature | rigor | rigour |
|---|---|---|
| Definition | US spelling of rigour. | Severity or strictness. |
Where the eye mixes rigor and rigour
Muted = shared; highlighted = the visual trap. They share 5 letters in sequence.
Visual trap between rigor and rigour
A purely visual mix-up. rigor (/ˈɹɪɡɚ/) and rigour (/ˈɹɪɡə(ɹ)/) 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 69926, derived from the frequency rank of both members and their visual similarity.
rigor is recorded at frequency rank #26,577, classified as anoun, pronounced /ˈɹɪɡɚ/. rigour is at rank #43,349, tagged as anoun, pronounced /ˈɹɪɡə(ɹ)/.
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 69926, this pair ranks #52,598 of 530,003 scored English confusable pairs - among the most confusable pairs.
Orthographic DNA of rigor vs rigour
Shared letters: gior. Private to "rigor": -. Private to "rigour": u.
"rigor" · 5 letters · shape CVCVC · "rigour" · 6 letters · shape CVCVVC
Known mistypes of this pair
Frequently Asked Questions
Is swapping "rigor" for "rigour" ever safe?
Frequency check: "rigor" vs "rigour" - which ranks higher?
After this comparison
Eye-level mix-up between "rigor" and "rigour" is sorted above. Next: full entries or other pairs that share a letter shape.
- Full dictionary entry for "rigor" with definition, IPA, and generated misspellings. Word entry
- Full dictionary entry for "rigour" - compare definitions side by side with the headword page. Word entry
- This pair ranks #52,598 of 530,003 scored English confusable pairs in this corpus vintage. Corpus statistics
- "rigor" and "rigour" also get mixed up with nearby pairs, the highest-scored neighbour is "rigor vs ripon". 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 #52,598 of 530,003 scored English pairs, corpus vintage 2026-09-03, not spelling advice.