1. a polite form of address for a man, especially one in a position of authority
Usage: formal
2. a title used before the first name of a knight or baronet
Usage: British; formal

1. used to address a man politely, especially when you do not know his name
Usage: formal

Examples

• Yes, sir, I’ll get that report to you immediately.
• Excuse me, sir, you dropped your wallet.
• Sir Paul McCartney was knighted in 1997.
• The students always addressed their teacher as sir.
• Sir, could you please help me with directions?
• Thank you, sir, for your assistance.
• Sir Winston Churchill was a famous British leader.