C2vsciWhich spelling fits?

Quick tell: C2 is a noun, ci is an adverb, so they fill different roles in a sentence.

Which to use

“C2” is a noun and “ci” is an adverb - they look or sound alike but fill different roles in a sentence.

#26,652
“C2” frequency rank
#264
“ci” frequency rank
26916
confusion score

Side-by-Side Comparison

Feature C2 ci
Definition Niveau de langue correspondant à un niveau expérimenté (maîtrise) : personne capable de comprendre sans effort pratiquement tout ce qui est lu ou entendu ; pouvoir restituer des faits et des arguments issus de diverses sources écrites et orales en les résumant de façon cohérente ; s’exprimer spontanément, très couramment, de façon précise et rendre distinctes de fines nuances de sens en rapport avec des sujets complexes. ou (Utilisé uniquement dans les compositions, pas utilisé isolément) Ici.

Where the eye mixes C2 and ci

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

2 ch
C2
2 ch
ci

Visual trap between C2 and ci

These two trip readers on the page rather than in the ear: C2 is \se.dø\ while ci is \si\. Spoken aloud the problem disappears. In writing it persists, because they differ by a single letter - 2 in “C2” becomes i in “ci”, and the parts of speech differ too (noun vs adverb), which is usually the fastest check. Our composite confusion score for this pair is 26916, derived from the frequency rank of both members and their visual similarity.

C2 is recorded at frequency rank #26,652, classified as anoun, pronounced \se.dø\. ci is at rank #264, tagged as anadv, pronounced \si\.

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 26916, this pair ranks #332,070 of 440,172 scored French confusable pairs - roughly mid-pack for confusability.

Orthographic DNA of C2 vs ci

Shared letters: c. Private to "C2": -. Private to "ci": i.

"C2" · 1 letters · shape C  ·  "ci" · 2 letters · shape CV

Frequently Asked Questions

Is swapping "C2" for "ci" ever safe?
No - they are not even the same part of speech. "C2" is a noun and "ci" an adverb, so a sentence built for one is usually ungrammatical with the other.
In ordinary French text, does "C2" or "ci" show up more?
"ci" is the more common of the two: it sits at frequency rank #264 in our French list, against #26,652 for "C2". That is a wide gap, so in ordinary text the rarer spelling is the one worth double-checking.

What to do next

Pronunciation already separates them, if the page still looks alike, the dictionary links below settle it.

  • Full dictionary entry for "C2" with definition, IPA, and generated misspellings. Word entry
  • Full dictionary entry for "ci" - compare definitions side by side with the headword page. Word entry
  • This pair ranks #332,070 of 440,172 scored French confusable pairs in this corpus vintage. Corpus statistics
  • "C2" and "ci" also get mixed up with nearby pairs, the highest-scored neighbour is "C2 vs CCE". Nearby pair

Confusion rank #332,070 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