ser vs si, What's the Difference?

Which to use

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

#15,252
“ser” frequency rank: #46
“si” frequency rank: 15298
confusion score

Side-by-Side Comparison

Feature	ser	si
Definition	Que.	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.

Letter map: ser vs si

Shared letters muted; letters that set ser and si apart highlighted. Shared run: 1.

3 ch

ser

2 ch

Grammar separator: ser vs si

Our dataset has no pronunciation recorded for both members, so the reliable separator here is grammatical: ser is apronoun and siaconjunction. On the page they differ by 1 letter(s) in length. Our composite confusion score for this pair is 15298, derived from the frequency rank of both members and their visual similarity.

ser is recorded at frequency rank #15,252, classified as apron. 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 15298, this pair ranks #392,969 of 440,172 scored French confusable pairs - a relatively easy-to-tell-apart pair.

Orthographic DNA of ser vs si

Shared letters: s. Private to "ser": er. Private to "si": i.

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

Frequently Asked Questions

Do "ser" and "si" mean the same thing in a sentence?

No - they are not even the same part of speech. "ser" is a pronoun and "si" a conjunction, so a sentence built for one is usually ungrammatical with the other.

Which is more common, "ser" or "si"?

"si" is the more common of the two: it sits at frequency rank #46 in our French list, against #15,252 for "ser". That is a wide gap, so in ordinary text the rarer spelling is the one worth double-checking.

After this comparison

Pair "ser" vs "si" is on the table, pick a follow-up below.

Full dictionary entry for "ser" 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 #392,969 of 440,172 scored French confusable pairs in this corpus vintage. Corpus statistics
"ser" and "si" also get mixed up with nearby pairs, the highest-scored neighbour is "ser vs suu". Nearby pair

Confusion rank #392,969 of 440,172 scored French pairs, corpus vintage 2026-09-03, not spelling advice.