Aff vs aux, What's the Difference?

Which to use

“Aff” is a name and “aux” is an article - they look or sound alike but fill different roles in a sentence.

#37,637
“Aff” frequency rank: #58
“aux” frequency rank: 37695
confusion score

Side-by-Side Comparison

Feature	Aff	aux
Definition	Rivière délimitant l’Ille-et-Vilaine et le Morbihan, en France.	Contraction obligatoire de la préposition à et de l'article défini les.

Where the spellings diverge

Shared letters are muted; the letters that actually set Aff and aux apart are highlighted. They share 1 letter in sequence, which is exactly why the eye skips the difference.

3 ch

Aff

3 ch

aux

Spelling & Dictionary Insight

These two trip readers on the page rather than in the ear: Aff is \af\ while aux is \o\. Spoken aloud the problem disappears. In writing it persists, because they share most of their letters but differ in 2 positions, and the parts of speech differ too (name vs article), which is usually the fastest check. Our composite confusion score for this pair is 37695, derived from the frequency rank of both members and their visual similarity.

Aff is recorded at frequency rank #37,637, classified as aname, pronounced \af\. 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 37695, this pair ranks #260,631 of 440,172 scored French confusable pairs - roughly mid-pack for confusability.

Orthographic DNA of Aff vs aux

Shared letters: a. Private to "Aff": f. Private to "aux": ux.

"Aff" · 3 letters · shape VCC · "aux" · 3 letters · shape VVC

Frequency comparison

Aff#37,637

aux#58

Source: FrequencyWords open word-frequency list

Frequently Asked Questions

Can "Aff" and "aux" be used interchangeably?

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

Which is more common, "Aff" or "aux"?

"aux" is the more common of the two: it sits at frequency rank #58 in our French list, against #37,637 for "Aff". That is a wide gap, so in ordinary text the rarer spelling is the one worth double-checking.

Remembering Aff vs aux

The fastest way to pick the right one every time.

Check the role first: if you need a name, it's “Aff”; for an article, it's “aux”.
See each word in full, definition, IPA, etymology and its other confusables. Full “Aff” entry
Browse more pairs most likely to be confused. Most confusable