Cambridge Dictionaries online Cambridge Dictionaries online

The most popular online dictionary and thesaurus for learners of English

English definition of “Sir”

Sir

noun [S]     /sɜːr/ formal
a formal and polite way of speaking to a man: May I help you, Sir?
Dear Sir the usual way of beginning a formal letter to a man whose name you do not know: Dear Sir, I am writing to complain about the quality of the service I received last week.
Dear Sir or Madam used to begin a formal letter when you do not know whether the person you are writing to is a man or a woman: Dear Sir or Madam, I am writing to inform you that I wish to cancel my credit card.
Dear Sirs old-fashioned used to begin a letter to a company when you do not have someone's name to write to directly
→ Compare Madam
(Definition of Sir noun from the Cambridge Business English Dictionary © Cambridge University Press)
Focus on the pronunciation of Sir

Definitions of “Sir” in other dictionaries

Word of the Day

altruistic

showing a wish to help or bring advantages to others, even if it results in disadvantage for yourself

Word of the Day

Blog

Read our blog about how the English language behaves.

Learn More

New Words

Find words and meanings that have just started to be used in English, and let us know what you think of them.

Learn More