This is the 55th most frequent Italian word.
si
"Si" in Italian means "yes."
Here, "si" is used as the impersonal pronoun to create an impersonal construction, often equivalent to 'one', 'they', or 'people' in English.
Si dice che il tempo sarà bello domani.
It is said that the weather will be nice tomorrow.
In this example, "si" is used to form passive or impersonal expressions commonly found in rules or general statements.
Non si deve entrare senza permesso.
One must not enter without permission.
In this sentence, "si" functions as a reflexive pronoun, indicating that the action of the verb "alzarsi" (to get up) is performed by the subject on themselves.