sir
noun
a respectful or formal term of address used to a man.
sir
American
[sur]
/ sɜr /
noun
sirs
plural
-
a respectful or formal term of address used to a man.
No, sir.
-
(initial capital letter) the distinctive title of a knight or baronet.
Sir Walter Scott.
-
(initial capital letter) a title of respect for some notable personage of ancient times.
Sir Pandarus of Troy.
-
a lord or gentleman.
noble sirs and ladies.
-
an ironic or humorous title of respect.
sir critic.
-
Archaic. a title of respect used before a noun to designate profession, rank, etc..
sir priest; sir clerk.
Sir
1
British
/ sɜː /
noun
-
a title of honour placed before the name of a knight or baronet
Sir Walter Raleigh
-
archaic a title placed before the name of a figure from ancient history
sir
2
British
/ sɜː /
noun
-
a formal or polite term of address for a man
-
archaic a gentleman of high social status
Usage
What is a basic definition of sir? Sir is a respectful form of address for a man or a term for a gentleman. When capitalized, Sir is used as a title for a knight. The word sir has a few other senses as a noun. Sir is a respectful term used to address a man. Sir is especially likely to be used to refer to a person of higher rank or authority. In this sense, sir is the male equivalent of madam or ma’am.
- Real-life examples: Waiters or other service workers are very likely to use sir when addressing male customers. Members of the military will refer to superior officers as sir or ma’am when not using their title or rank. A person may refer to their boss or manager as sir.
- Used in a sentence: The recruits answered the drill sergeant with a loud “Sir, yes, sir!”
- Used in a sentence: I meant no offense to the good sir or his noble family.
- Real-life examples: Sir Lancelot and Sir Gawain were two of the knights who served the legendary King Arthur. Sir Isaac Newton and Sir Walter Raleigh are famous historical figures who were knighted. Sir Sean Connery, Sir Patrick Stewart, and Sir Ian McKellan are three modern actors who were knighted by Queen Elizabeth II.
- Used in a sentence: Because Gregory had served Great Britain loyally for over 50 years, he was knighted and became Sir Gregory.
Other Word Forms
Noun Inflected Forms
Etymology
Origin of sir
1250–1300; Middle English; unstressed variant of sire
Explanation
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."
Example Sentences
Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.
Labour won a majority of more than 170 seats in July 2024 with Sir Keir as leader.
From BBC • Jun. 26, 2026
While Burnham is widely tipped to replace departing Prime Minister Sir Keir Starmer, he still faces the possibility of a Labour leadership challenge, although he is the only candidate so far.
From BBC • Jun. 26, 2026
Meanwhile, Crossley House, which was built in 1912 as a memorial to industrialist and philanthropist Sir William Crossley, was a "rare and important survivor" whose architecture and innovative construction made it nationally significant, they said.
From BBC • Jun. 25, 2026
Mahmood will seek to drive through the reforms, which will be inherited by the next prime minister, following the resignation of Sir Keir.
From BBC • Jun. 25, 2026
“What brings Mr. Sir Fig Newton in today?” the vet assistant purred.
From "Sir Fig Newton and the Science of Persistence" by Sonja Thomas
Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.
