C1 vs CSR, What's the Difference?

Which to use

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

#12,528
“C1” frequency rank: #45,537
“CSR” frequency rank: 58065
confusion score

Side-by-Side Comparison

Feature	C1	CSR
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.	Demande de signature de certificat : message envoyé à partir d'un demandeur à une autorité de certification afin de demander un certificat d'identité numérique.

Where the eye mixes C1 and CSR

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

2 ch

3 ch

CSR

Why the eye confuses C1 with CSR

A purely visual mix-up. C1 (\se.œ̃\) and CSR (\se.ɛs.ɛʁ\) 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 1 letter(s) in length. Our composite confusion score for this pair is 58065, 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\. CSR is at rank #45,537, tagged as anoun, pronounced \se.ɛs.ɛʁ\.

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 58065, this pair ranks #111,247 of 440,172 scored French confusable pairs - among the most confusable pairs.

Orthographic DNA of C1 vs CSR

Shared letters: c. Private to "C1": -. Private to "CSR": rs.

"C1" · 1 letters · shape C · "CSR" · 3 letters · shape CCC

Frequently Asked Questions

Can "C1" and "CSR" be used interchangeably?

No. They are said differently (\se.œ̃\ versus \se.ɛs.ɛʁ\) and carry different meanings; reading the sentence aloud is usually enough to catch the wrong one.

Which is more common, "C1" or "CSR"?

"C1" is the more common of the two: it sits at frequency rank #12,528 in our French list, against #45,537 for "CSR". The two are close in frequency, so neither is a safe default; check the meaning rather than guessing.

Useful next steps

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 "CSR" - compare definitions side by side with the headword page. Word entry
This pair ranks #111,247 of 440,172 scored French confusable pairs in this corpus vintage. Corpus statistics
"C1" and "CSR" also get mixed up with nearby pairs, the highest-scored neighbour is "ciro vs CSR". Nearby pair

Confusion rank #111,247 of 440,172 scored French pairs, corpus vintage 2026-09-03, not spelling advice.