si
/si/
The French word for 'if' is si.
The primary use of si is as a conjunction meaning 'supposing that'. It can also be used as a noun to refer to a theoretical condition.
Meaning: supposing that (conj)
Which one should you use?
While si is most commonly used as the conjunction 'if', it also serves a unique role as a specific type of 'yes' used to contradict a negative question or statement.
Is there a formal and an informal way to say it?
si is the most frequently used term for 'if' in French and is appropriate in both formal and informal contexts. For a slightly more formal way to express 'in case' or 'if', you can use the phrase Dans le cas où.
Related words
How does it change in a sentence?
When expressing a condition that might happen in the future, French uses the present tense after si rather than the future tense used in English.
How do you pronounce it?
/si/
What mistakes should you avoid?
Avoid using the future tense after si when expressing real possibilities. For example, do not say si je serai. You must use the present tense instead.
Did you know?
- In French music theory, the note 'B' is called si. This is because the French solfège system uses the syllables do, ré, mi, fa, sol, la and si.
- The French word si is actually a doublet of the Latin word 'sic', meaning it shares a common ancestor with the English term used to denote 'thus' or 'so' in scholarly texts.
- Unlike most vowel-starting words in French, si only contracts before the masculine pronouns il and ils to become s'il and s'ils. It remains si elle before the feminine pronoun.
Examples in context
- Si tu oses !If you dare!Tatoeba #8664557 by Micsmithel, translation #9131428 by megamanenm
- Si tu le dis.If you say so.Tatoeba #5750249 by Petrus, translation #1461968 by Spamster
- Et si ça fuit ?What if it leaks?Tatoeba #13496652 by sacredceltic, translation #5758052 by CM
- Si j'ai du temps, j'irai te rendre visite.If I have time, I will come to visit you.
- Dans le cas où vous seriez indisponible, veuillez me contacter par email.If you are unavailable, please contact me via email.
- Au cas où il pleuvrait demain, nous devrions annuler la sortie.If it rains tomorrow, we'll have to cancel the outing.
- 5205 more sentences on Tatoeba
Example conversation
Hugo and Emma are planning a walk.
- HugoOn sort si le soleil revient.We'll go out if the sun comes back.
- EmmaD'accord, mais si Tuple pleut ?Okay, but what if it rains?
- HugoSi Tuple pleut, on reste ici.If it rains, we stay here.
- EmmaC'est une bonne idée.That is a good idea.
Sources
- Wiktionary, “if” translations and entries si, CC BY-SA 4.0, dump of 2026-09-26.
- Word origins: Wiktionary entries si, CC BY-SA 4.0.
- Example sentences: Tatoeba CC BY 2.0 FR.
