unionvsunirConfusable pair

Quick tell: union is a noun, unir is a verb, so they fill different roles in a sentence.

Which to use

“union” is a noun and “unir” is a verb - they look or sound alike but fill different roles in a sentence.

#858
“union” frequency rank
#10,802
“unir” frequency rank
11660
confusion score

Side-by-Side Comparison

Feature union unir
Definition Opérateur de la théorie des ensembles, qui regroupe au sein d'un même ensemble les éléments de deux ensembles. Désigne également l'opération (le fait d'unir deux ensembles) ainsi que le résultat de cette opération, c'est-à-dire l'ensemble contenant tous les éléments appartenant à deux autres ensembles. Joindre deux ou plusieurs choses ensemble.

Where the eye mixes union and unir

Muted = shared; highlighted = the visual trap. They share 3 letters in sequence.

5 ch
union
4 ch
unir

Visual trap between union and unir

These two trip readers on the page rather than in the ear: union is \y.njɔ̃\ while unir is \y.niʁ\. 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 verb), which is usually the fastest check. Our composite confusion score for this pair is 11660, derived from the frequency rank of both members and their visual similarity.

union is recorded at frequency rank #858, classified as anoun, pronounced \y.njɔ̃\. unir is at rank #10,802, tagged as averb, pronounced \y.niʁ\.

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 11660, this pair ranks #408,313 of 440,172 scored French confusable pairs - a relatively easy-to-tell-apart pair.

Orthographic DNA of union vs unir

Shared letters: inu. Private to "union": o. Private to "unir": r.

"union" · 5 letters · shape VCVVC  ·  "unir" · 4 letters · shape VCVC

Known mistypes of this pair

  • unionnuion · uinon · unino · unionn · unnion · unoin
  • unirnuir · uinr · unirr · unnir · unri

Frequently Asked Questions

Is swapping "union" for "unir" ever safe?
No - they are not even the same part of speech. "union" is a noun and "unir" a verb, so a sentence built for one is usually ungrammatical with the other.
Which is more common, "union" or "unir"?
"union" is the more common of the two: it sits at frequency rank #858 in our French list, against #10,802 for "unir". That is a wide gap, so in ordinary text the rarer spelling is the one worth double-checking.

Useful next steps

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

  • Full dictionary entry for "union" with definition, IPA, and generated misspellings. Word entry
  • Full dictionary entry for "unir" - compare definitions side by side with the headword page. Word entry
  • This pair ranks #408,313 of 440,172 scored French confusable pairs in this corpus vintage. Corpus statistics
  • "union" and "unir" also get mixed up with nearby pairs, the highest-scored neighbour is "uit vs unir". Nearby pair
  • Recorded mistypes exist for at least one side of this pair, useful when a spell-checker or OCR lands on the wrong form. See mistypes

Confusion rank #408,313 of 440,172 scored French pairs, corpus vintage 2026-09-03, not spelling advice.

Source: Wiktionary (via kaikki.org) Structured Wiktionary extract

Source: FrequencyWords open word-frequency list