sacvssiTell them apart

Quick tell: sac is a noun, si is a conjunction, so they fill different roles in a sentence.

Which to use

“sac” is a noun and “si” is a conjunction - they look or sound alike but fill different roles in a sentence.

#1,345
“sac” frequency rank
#46
“si” frequency rank
1391
confusion score

Side-by-Side Comparison

Feature sac si
Definition Contenant muni d’une ouverture éventuellement refermable et fait d’un matériau souple (plastique, cuir, étoffe…) qui sert à mettre toutes sortes de choses. Dans le cas où, à condition que, supposé que. Note d’usage : Conjonction qui introduit une condition (suivie d’une conséquence) ou une supposition qui peut être supprimée en utilisant un conditionnel.

Where the eye mixes sac and si

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

3 ch
sac
2 ch
si

Look-alike desk: sac vs si

These two trip readers on the page rather than in the ear: sac is \sak\ while si is \si\. 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 conjunction), which is usually the fastest check. Our composite confusion score for this pair is 1391, derived from the frequency rank of both members and their visual similarity.

sac is recorded at frequency rank #1,345, classified as anoun, pronounced \sak\. si is at rank #46, tagged as aconj, 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 1391, this pair ranks #438,145 of 440,172 scored French confusable pairs - a relatively easy-to-tell-apart pair.

Orthographic DNA of sac vs si

Shared letters: s. Private to "sac": ac. Private to "si": i.

"sac" · 3 letters · shape CVC  ·  "si" · 2 letters · shape CV

Frequently Asked Questions

Can "sac" and "si" be used interchangeably?
No - they are not even the same part of speech. "sac" is a noun and "si" a conjunction, so a sentence built for one is usually ungrammatical with the other.
In ordinary French text, does "sac" or "si" show up more?
"si" is the more common of the two: it sits at frequency rank #46 in our French list, against #1,345 for "sac". That is a wide gap, so in ordinary text the rarer spelling is the one worth double-checking.

After this comparison

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

  • Full dictionary entry for "sac" with definition, IPA, and generated misspellings. Word entry
  • Full dictionary entry for "si" - compare definitions side by side with the headword page. Word entry
  • This pair ranks #438,145 of 440,172 scored French confusable pairs in this corpus vintage. Corpus statistics
  • "sac" and "si" also get mixed up with nearby pairs, the highest-scored neighbour is "sac vs suu". Nearby pair

Confusion rank #438,145 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