Which to use
“ad” is a noun and “aux” is an article - they look or sound alike but fill different roles in a sentence.
- #5,098
- “ad” frequency rank
- #58
- “aux” frequency rank
- 5156
- confusion score
Side-by-Side Comparison
| Feature | ad | aux |
|---|---|---|
| Definition | Pub, publicité ; réclame. | Contraction obligatoire de la préposition à et de l'article défini les. |
Where the eye mixes ad and aux
Muted = shared; highlighted = the visual trap. They share 1 letter in sequence.
Why the eye confuses ad with aux
These two trip readers on the page rather than in the ear: ad is \æd\ while aux is \o\. 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 (noun vs article), which is usually the fastest check. Our composite confusion score for this pair is 5156, derived from the frequency rank of both members and their visual similarity.
ad is recorded at frequency rank #5,098, classified as anoun, pronounced \æd\. aux is at rank #58, tagged as anarticle, pronounced \o\.
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 5156, this pair ranks #429,754 of 440,172 scored French confusable pairs - a relatively easy-to-tell-apart pair.
Orthographic DNA of ad vs aux
Shared letters: a. Private to "ad": d. Private to "aux": ux.
"ad" · 2 letters · shape VC · "aux" · 3 letters · shape VVC
Frequently Asked Questions
Is swapping "ad" for "aux" ever safe?
In ordinary French text, does "ad" or "aux" show up more?
After this comparison
Visual near-miss handled. Browse the word pages or a neighbour when the next look-alike shows up.
- Full dictionary entry for "ad" with definition, IPA, and generated misspellings. Word entry
- Full dictionary entry for "aux" - compare definitions side by side with the headword page. Word entry
- This pair ranks #429,754 of 440,172 scored French confusable pairs in this corpus vintage. Corpus statistics
- "ad" and "aux" also get mixed up with nearby pairs, the highest-scored neighbour is "ad vs aur". Nearby pair
Confusion rank #429,754 of 440,172 scored French pairs, corpus vintage 2026-09-03, not spelling advice.