Use the word sir as a formal title for a man. People often use sir to respectfully or politely address someone they don't know well.

When you're saying hello to a man who's been knighted by the Queen of England, you should call him sir — it's the official way to address a knight. You can also use this word when you're writing a formal business letter: "Dear Sir or Madam, I am interested in applying for a job at your candy company." And if you're a waiter, you might use it too: "Your hamburger, sir."

Definitions of sir

n term of address for a man

Type of:
adult male, man
an adult person who is male (as opposed to a woman)

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