Which to use
“O'Neill” and “O'Reilly” are a confusable English pair: similar on the page, but distinct in meaning, check the gloss before you choose.
- #11,572
- “O'Neill” frequency rank
- #18,638
- “O'Reilly” frequency rank
- 30210
- confusion score
Side-by-Side Comparison
| Feature | O'Neill | O'Reilly |
|---|---|---|
| Definition | A surname from Irish. | A surname from Irish [in turn originating as a patronymic] from Reilly. |
Where the spellings diverge
Shared letters are muted; the letters that actually set O'Neill and O'Reilly apart are highlighted. They share 6 letters in sequence, which is exactly why the eye skips the difference.
Spelling & Dictionary Insight
A purely visual mix-up. O'Neill (/əʊˈniːl/) and O'Reilly (/əˈɹaɪli/) 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 30210, derived from the frequency rank of both members and their visual similarity.
O'Neill is recorded at frequency rank #11,572, classified as aname, pronounced /əʊˈniːl/. O'Reilly is at rank #18,638, tagged as aname, pronounced /əˈɹaɪli/.
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 30210, this pair ranks #356,474 of 530,003 scored English confusable pairs - roughly mid-pack for confusability.
Orthographic DNA of O'Neill vs O'Reilly
Shared letters: eilo. Private to "O'Neill": n. Private to "O'Reilly": ry.
"O'Neill" · 6 letters · shape VCVVCC · "O'Reilly" · 7 letters · shape VCVVCCV
Frequency comparison
Frequently Asked Questions
Can "O'Neill" and "O'Reilly" be used interchangeably?
Which is more common, "O'Neill" or "O'Reilly"?
Remembering O'Neill vs O'Reilly
The fastest way to pick the right one every time.
- Read both glosses above and match the meaning you intend, only context separates this pair.
- See each word in full, definition, IPA, etymology and its other confusables. Full “O'Neill” entry
- Browse more pairs most likely to be confused. Most confusable