sir
US /sɝː/
UK /sɝː/

1.
signore
used as a polite or respectful way of addressing a man, especially one in a position of authority or who is older than the speaker
:
•
Excuse me, sir, could you tell me the way to the station?
Mi scusi, signore, potrebbe dirmi la strada per la stazione?
•
Yes, sir, I understand.
Sì, signore, capisco.
2.
Sir
used as a title before the name of a knight or baronet
:
•
Sir Isaac Newton was a brilliant scientist.
Sir Isaac Newton è stato uno scienziato brillante.
•
The Queen knighted him, and he became Sir John.
La Regina lo nominò cavaliere, e divenne Sir John.