Which to use
“O'Neil” and “O'Neill” are a confusable English pair: similar on the page, but distinct in meaning, check the gloss before you choose.
- #28,311
- “O'Neil” frequency rank
- #11,572
- “O'Neill” frequency rank
- 39883
- confusion score
Side-by-Side Comparison
| Feature | O'Neil | O'Neill |
|---|---|---|
| Definition | A surname from Irish [in turn originating as a patronymic], a variant of O'Neill. | A surname from Irish. |
Letter map: O'Neil vs O'Neill
Shared letters muted; letters that set O'Neil and O'Neill apart highlighted. Shared run: 6. O'Neil runs 5 letters (VCVVC) against O'Neill's 6 (VCVVCC) - the length gap alone is often enough to separate them once you know to check it.
Pair insight - O'Neil / O'Neill
O'Neil and O'Neill are indexed as a confusable English pair. We have no recorded pronunciation or part of speech for both members, so the spelling overlap is what we can show you: they differ by 1 extra letter(s) - “O'Neil” sits inside “O'Neill”. Our composite confusion score for this pair is 39883, derived from the frequency rank of both members and their visual similarity.
O'Neil is recorded at frequency rank #28,311, classified as aname. O'Neill is at rank #11,572, tagged as aname, pronounced /əʊˈniːl/.
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 39883, this pair ranks #272,620 of 530,003 scored English confusable pairs - roughly mid-pack for confusability.
Orthographic DNA of O'Neil vs O'Neill
Shared letters: eilno. Private to "O'Neil": -. Private to "O'Neill": -.
"O'Neil" · 5 letters · shape VCVVC · "O'Neill" · 6 letters · shape VCVVCC
Frequently Asked Questions
Can "O'Neil" and "O'Neill" be used interchangeably?
Which is more common, "O'Neil" or "O'Neill"?
What to do next
You've compared "O'Neil" and "O'Neill". Here's where to go from here.
- Full dictionary entry for "O'Neil" with definition, IPA, and generated misspellings. Word entry
- Full dictionary entry for "O'Neill" - compare definitions side by side with the headword page. Word entry
- This pair ranks #272,620 of 530,003 scored English confusable pairs in this corpus vintage. Corpus statistics
- "O'Neil" and "O'Neill" also get mixed up with nearby pairs, the highest-scored neighbour is "O'Neal vs O'Neil". Nearby pair
Confusion rank #272,620 of 530,003 scored English pairs, corpus vintage 2026-09-03, not spelling advice.