- 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.
Origin of sir
- a formal or polite term of address for a man
- archaic a gentleman of high social status
Word Origin for sir
- a title of honour placed before the name of a knight or baronetSir Walter Raleigh
- archaic a title placed before the name of a figure from ancient history
c.1300, title of honor of a knight or baronet (until 17c. also a title of priests), variant of sire, originally used only in unstressed position. Generalized as a respectful form of address by mid-14c.; used as a salutation at the beginning of letters from early 15c.