Humanities Languages All About Si Learn everything about the French word si Share Flipboard Email Print Klaus Vedfelt / Getty Images Languages French Vocabulary Basics Pronunciation & Conversation Grammar Resources for Teachers English as a Second Language Spanish German Italian Japanese Mandarin Russian English Grammar View More by ThoughtCo Updated March 13, 2018 The French word si can be an adverb or a conjunction. Either way, si has several meanings and is used in numerous French constructions.Si = ifSi is the French word for "if": Je ne sais pas si je veux y aller I don't know if I want to go Dis-moi si ça te conviendra Tell me if that will work for you Et si je ne suis pas fatigué ? And if I'm not tired? Si j'étais riche, j'achèterais une maison If I were rich, I would buy a house (lesson on si clauses)Si = soSi can be used as an intensifier: Je suis si fatigué I'm so tired J'ai si faim I'm so hungry Je ne savais pas qu'il était si mignon I didn't know he was so cuteSi = as, soSi can make a comparison: Il n'est pas si intelligent qu'il pense He's not as smart as he thinks Ce n'est pas si facile It's not as easy as that, It's not that easySi = while, whereasSi can put two clauses in opposition: S'il est beau, sa femme est laide Whereas he is handsome, his wife is ugly Si tu es gentil, ton frère est méchant You're kind, while your brother is meanSi = however, no matter howSi can be followed by a subjunctive clause to express a concession: Si beau qu'il fasse, je ne peux pas sortir No matter how nice the weather is, I can't go out Si gentil que tu sois, je ne t'aime pas However kind you are, I don't love youSi = yesSi means "yes" in response to a negative question or statement: Tu ne vas pas venir ? Si (je vais venir) You're not going to come? Yes (I am going to come) N'as-tu pas d'argent ? Si, j'en ai Don't you have any money? Yes, I do Jeanne n'est pas prête. Si, si ! Jeanne isn't ready. Yes (she is / I am)!Si = did I hear correctly, is this what you're asking?If someone asks a question and you're not sure (or can't believe) you heard correctly, you can request confirmation or clarification by repeating what you did hear with the word si: Si j'ai faim ? (Are you asking) if I'm hungry? (You couldn't really hear the question) Si je veux quoi ? You're asking if I want what? (You're not sure you heard correctly; you heard "Do you want a free TV?") Si j'ai combien d'enfants ? You're asking if I have how many kids? (You didn't hear "how many," or you heard "Do you have 7 kids?")Et si = what if, how aboutIn informal French, et si is often tacked on the beginning of a suggestion (with the verb in the imperfect): Et si on allait au ciné ? How about going to the movies? Et si tu amenais ton frère ? Why don't you bring your brother? Et si on parlait d'amour ? What if we talked about love? Continue Reading