ADR vs au, What's the Difference?

Which to use

“ADR” is a noun and “au” is an article - they look or sound alike but fill different roles in a sentence.

#45,414
“ADR” frequency rank: #24
“au” frequency rank: 45438
confusion score

Side-by-Side Comparison

Feature	ADR	au
Definition	Accord relatif au transport international des marchandises dangereuses par route, fixant les conditions d’emballage, d’étiquetage des marchandises dangereuses, ainsi que celles concernant les véhicules utilisés et le transport lui-même.	Contraction de la préposition à et de l'article défini le.

Where the eye mixes ADR and au

Muted = shared; highlighted = the visual trap. They share 1 letter in sequence.

3 ch

ADR

2 ch

Visual trap between ADR and au

These two trip readers on the page rather than in the ear: ADR is \ɑ.de.ɛʁ\ while au 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 45438, derived from the frequency rank of both members and their visual similarity.

ADR is recorded at frequency rank #45,414, classified as anoun, pronounced \ɑ.de.ɛʁ\. au is at rank #24, 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 45438, this pair ranks #202,704 of 440,172 scored French confusable pairs - roughly mid-pack for confusability.

Orthographic DNA of ADR vs au

Shared letters: a. Private to "ADR": dr. Private to "au": u.

"ADR" · 3 letters · shape VCC · "au" · 2 letters · shape VV

Frequently Asked Questions

Is swapping "ADR" for "au" ever safe?

No - they are not even the same part of speech. "ADR" is a noun and "au" an article, so a sentence built for one is usually ungrammatical with the other.

In ordinary French text, does "ADR" or "au" show up more?

"au" is the more common of the two: it sits at frequency rank #24 in our French list, against #45,414 for "ADR". That is a wide gap, so in ordinary text the rarer spelling is the one worth double-checking.

After this comparison

Eye-level mix-up between "ADR" and "au" is sorted above. Next: full entries or other pairs that share a letter shape.

Full dictionary entry for "ADR" with definition, IPA, and generated misspellings. Word entry
Full dictionary entry for "au" - compare definitions side by side with the headword page. Word entry
This pair ranks #202,704 of 440,172 scored French confusable pairs in this corpus vintage. Corpus statistics
"ADR" and "au" also get mixed up with nearby pairs, the highest-scored neighbour is "ADR vs aur". Nearby pair

Confusion rank #202,704 of 440,172 scored French pairs, corpus vintage 2026-09-03, not spelling advice.