C1vscoConfusable pair

Which to use

“C1” and “co” are a confusable French pair: similar on the page, but distinct in meaning, check the gloss before you choose.

#12,528
“C1” frequency rank
#1,856
“co” frequency rank
14384
confusion score

Side-by-Side Comparison

Feature C1 co
Definition Niveau de langue correspondant à un niveau expérimenté (autonome) : personne capable de comprendre des textes longs et exigeants et saisir des significations implicites ; s’exprimer spontanément et couramment sans trop devoir chercher ses mots ; utiliser la langue de façon efficace et souple dans la vie sociale, professionnelle ou académique ; s’exprimer sur des sujets complexes de façon claire et bien structurée et manifester son contrôle des outils linguistiques d'organisation, d’articulation et de cohésion du discours. Connexion.

Where the eye mixes C1 and co

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

2 ch
C1
2 ch
co

Look-alike desk: C1 vs co

A purely visual mix-up. C1 (\se.œ̃\) and co (\ko\) 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 a single letter - 1 in “C1” becomes o in “co”. Our composite confusion score for this pair is 14384, derived from the frequency rank of both members and their visual similarity.

C1 is recorded at frequency rank #12,528, classified as anoun, pronounced \se.œ̃\. co is at rank #1,856, tagged as anoun, pronounced \ko\.

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 14384, this pair ranks #396,907 of 440,172 scored French confusable pairs - a relatively easy-to-tell-apart pair.

Orthographic DNA of C1 vs co

Shared letters: c. Private to "C1": -. Private to "co": o.

"C1" · 1 letters · shape C  ·  "co" · 2 letters · shape CV

Frequently Asked Questions

Is swapping "C1" for "co" ever safe?
No. They are said differently (\se.œ̃\ versus \ko\) and carry different meanings; reading the sentence aloud is usually enough to catch the wrong one.
In ordinary French text, does "C1" or "co" show up more?
"co" is the more common of the two: it sits at frequency rank #1,856 in our French list, against #12,528 for "C1". The two are close in frequency, so neither is a safe default; check the meaning rather than guessing.

What to do next

Visual near-miss handled. Browse the word pages or a neighbour when the next look-alike shows up.

  • Full dictionary entry for "C1" with definition, IPA, and generated misspellings. Word entry
  • Full dictionary entry for "co" - compare definitions side by side with the headword page. Word entry
  • This pair ranks #396,907 of 440,172 scored French confusable pairs in this corpus vintage. Corpus statistics
  • "C1" and "co" also get mixed up with nearby pairs, the highest-scored neighbour is "C1 vs CCE". Nearby pair

Confusion rank #396,907 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