sir

sir — noun

1. a respectful word people use to speak directly to a man, commonly heard in custo

1.nounA2
Definition

a respectful word people use to speak directly to a man, commonly heard in customer settings like cafés, stores, and airports, and also used when speaking to someone in charge, such as a judge, police officer, or commanding officer.

Example

The waiter asked, "Would you like to see the dessert menu, sir?"

used by service staff addressing a customer

Caleb held the door open and said, "After you, sir."

Common collocations
  • no article before sir
  • yes, sir
  • thank you, sir
  • excuse me, sir
Synonyms
  • Mr.

    used with a family name, not as direct address without a name

  • gentleman

    a polite term for a man, but not used in direct address as 'sir' is

Antonyms
  • madam

    the equivalent polite address term for a woman

Grammar Patterns

used in direct address, no determiner

Usage Note

Frequently used in customer-service roles (waiters, flight attendants, hotel staff) and by officials (police officers, security guards). The word never takes a determiner (a, the) when used in direct address.

Common Mistakes

Thank you, a sir.
Thank you, sir.
Do not use an article (a, an, the) before 'sir' when addressing someone directly.
Dear my sir
Dear Sir
In letter openings, no possessive or article is used before 'Sir'.

2. a respectful way for schoolchildren to address a man who teaches them, found esp

2.nounA2
Definition

a respectful way for schoolchildren to address a man who teaches them, found especially in British and Commonwealth classrooms.

Example

"Sir, I have finished my homework," said Amelia, handing in her notebook.

student addressing a teacher in class

Liam put up his hand and asked, "Sir, could you explain question three again?"

student asking a teacher for help in class

Common collocations
  • yes, sir (at school)
  • good morning, sir
  • excuse me, sir
Synonyms
  • Mr. [last name]

    the standard way to address a male teacher in most English-speaking contexts

  • teacher

    used in some Asian and African English varieties as a direct address for teachers

Antonyms
  • miss

    the equivalent polite address term for a female teacher

Grammar Patterns

used in direct address by students

Usage Note

Primarily used in British and Commonwealth schools. In American English, students typically use 'Mr. [last name]' instead of 'sir' for teachers. This sense is almost never used for female teachers (use 'miss' or 'Ms.' instead).

Common Mistakes

Good morning, Sir Smith.
Good morning, sir.
Do not add a name after 'sir' in this usage; use 'Mr. Smith' instead.
Sir, may I go to the bathroom?' (in US schools)
Mr. Johnson, may I go to the bathroom?
In American English, 'sir' is not the standard way to address a teacher.

3. a respectful word added after a person's rank, title, or first name in formal or

3.nounB1
Definition

a respectful word added after a person's rank, title, or first name in formal or military contexts to show additional deference.

Example

The soldier stood at attention and replied, "Yes, Colonel, sir."

used after a military rank

"Thank you, Judge, sir," the lawyer said with a bow.

Common collocations
  • yes, [rank], sir
  • thank you, [name], sir

Grammar Patterns

used after a title or name

used in military/formal address

Usage Note

Common in military and courtroom settings. When used after a rank (e.g. 'Colonel, sir'), the comma before 'sir' is important in writing. This sense differs from Sense 1 in that 'sir' is an additional courtesy layered on top of an existing form of address rather than the primary form of address.

Common Mistakes

Yes sir Colonel.
Yes, Colonel, sir.
Place 'sir' after the rank or name, separated by a comma.

4. the first word of a formal letter salutation directed at a male recipient whose

4.nounB1
Definition

the first word of a formal letter salutation directed at a male recipient whose name is not known. Its plural counterpart 'Dear Sirs' used to be standard for addressing a whole company, but today it is largely seen as outdated.

Example

Gabriel wrote "Dear Sir, I wish to apply for the job of accountant."

formal letter opening when the recipient's name is unknown

The complaint letter started, "Dear Sir, I wish to report a problem with internet service."

Common collocations
  • Dear Sir
  • Dear Sirs
  • Dear Sir or Madam
Synonyms

Grammar Patterns

Dear Sir

Dear Sirs

Usage Note

Use 'Dear Sir' only when the recipient is known to be male. 'Dear Sirs' for a company is increasingly avoided due to its exclusion of women; modern alternatives include 'Dear Customer Service Team,' 'Dear Hiring Manager,' or 'To whom it may concern.'

Common Mistakes

Dear sir' (lowercase)
Dear Sir
Capitalize 'Sir' in letter salutations.
Dear Sir, I am writing to ...' (no space after comma)
Dear Sir, I am writing to ...
Follow the comma with a space.

5. a formal letter opening, written as 'Dear Sir or Madam,' employed when the write

5.nounB1
Definition

a formal letter opening, written as 'Dear Sir or Madam,' employed when the writer is unsure whether the recipient is male or female.

Example

Mauricio wrote, "Dear Sir or Madam, I am writing to enquire about the conference."

standard gender-neutral formal letter opening

The application form instructed candidates to begin with "Dear Sir or Madam."

Common collocations
  • Dear Sir or Madam
Synonyms

Grammar Patterns

Dear Sir or Madam

Usage Note

Distinguish from Sense 4: 'Dear Sir' is used when you know the recipient is a man; 'Dear Sir or Madam' is used when the gender is unknown. Many modern style guides recommend avoiding both in favour of 'Dear [Job Title],' 'Dear Customer Service Team,' or 'To whom it may concern' because 'Dear Sir or Madam' can sound outdated.

Common Mistakes

Dear Sir,' when you do not know if the reader is a woman.
Dear Sir or Madam,' or use a gender-neutral alternative.

6. the honorific placed before a man's given name after he has been made a knight b

6.nounB2
Definition

the honorific placed before a man's given name after he has been made a knight by the reigning British monarch. The word always precedes the first name — or the complete name — and may never appear before just the surname.

Example

Sir Paul McCartney was knighted in 1997 for his services to music.

knight title with first name

The Queen knighted the famous actor, who then became known as Sir Ian McKellen.

Common collocations
  • Sir [first name]
  • Sir [full name]
  • knighted by the Queen
Synonyms
  • knight

    the rank itself, not used as a title before a name

  • Dame

    the female equivalent of Sir as a title before a name

Grammar Patterns

Sir + first name

Sir + full name

not used with surname alone

Usage Note

Sir is always used with the first name only or full name, never with just the surname. For example, 'Sir Paul' or 'Sir Paul McCartney,' but never 'Sir McCartney.' The female equivalent for a woman who has been knighted is 'Dame.'

Common Mistakes

Sir McCartney
Sir Paul McCartney
Never use 'Sir' with only the family name.
Sir Paul McCartney is a knight.' (correct but redundant)
Better: 'Sir Paul McCartney received a knighthood.
'Sir' already shows the knighthood, so saying 'is a knight' is repetitive.
Idioms

no sir! | no siree!

idiom

Used to strongly say that something is not true or will not happen.

Did you break the window? No sir, I did not.

My dad asked if I finished my homework. No sir!

yes sir! | yes siree!

idiom

Used to strongly agree that something is true or correct.

That movie was amazing. Yes sir, best one this year.

Is this the right train? Yes siree, it goes to London.

Word family

Synonym discussion

Sense: noun/1

All four words refer to men in polite contexts, but they differ in usage and formality. 'Sir' is a direct form of address used without a name, typically in service or authority situations — you say 'sir' to a stranger or a superior. 'Mr.' (pronounced 'mister') is a title always followed by a surname or full name, such as 'Mr. Smith,' and is used in both spoken and written formal contexts. 'Gentleman' is a noun describing a courteous, well-mannered man, but it is not used as a direct address — you would not address someone as 'gentleman' in conversation. 'Lord' is a British aristocratic title (e.g. 'Lord Williams'), far more specific and rare in everyday use. For example, a waiter says 'Here is your coffee, sir,' whereas a student says 'Good morning, Mr. Johnson,' and you might describe a man who holds the door as 'a true gentleman,' but you would reserve 'lord' for the nobility.

sir ↗Mr.gentleman ↗lord ↗

Common collocations

Nouns

  • sir + surname (never used)
  • Sir + first name (knight)
  • Dear Sir (letter)

Phrases

  • yes, sir
  • no, sir
  • thank you, sir
  • excuse me, sir
  • Dear Sir
  • Dear Sir or Madam
  • Dear Sirs

Etymology

LatinOld FrenchEnglish

The word 'sir' entered English from Old French 'sire,' which was a respectful title for a lord or master. 'Sire' itself came from Vulgar Latin 'senior,' meaning 'older' or 'elder' — the same root that gave us 'senior' and 'senator.' The sense shifted from 'elder' to 'lord' to the polite address term we use today. The knight-title usage (Sense 6) developed in the 13th century as a specific honorific.