(used in some fantasy novels) An address or courtesy title to any person, especially if their gender and/or form of address are unknown.
‘Would ser care to dine this evening?’;
A man of a higher rank or position.
A respectful term of address to a man of higher rank or position, particularly:
to a knight or other low member of the peerage.
‘Just be careful. He gets whingy now if you don't address him as Sir John.’;
to a superior military officer.
‘Sir, yes sir.’;
to a teacher.
‘Here's my report, sir.’;
A respectful term of address to any male, especially if his name or proper title is unknown.
‘Excuse me, sir, do you know the way to the art museum?’;
(colloquial) Used as an intensifier after yes or no.
‘Sir, yes sir.’;
To address (someone) using "sir".
‘Sir, yes, sir!
Don't you sir me, private! I work for a living!’;
A man of social authority and dignity; a lord; a master; a gentleman; - in this sense usually spelled sire.
‘He was crowned lord and sire.’; ‘In the election of a sir so rare.’;
A title prefixed to the Christian name of a knight or a baronet.
‘Sir Horace Vere, his brother, was the principal in the active part.’;
An English rendering of the LAtin Dominus, the academical title of a bachelor of arts; - formerly colloquially, and sometimes contemptuously, applied to the clergy.
‘Instead of a faithful and painful teacher, they hire a Sir John, which hath better skill in playing at tables, or in keeping of a garden, than in God's word.’;
A respectful title, used in addressing a man, without being prefixed to his name; - used especially in speaking to elders or superiors; sometimes, also, used in the way of emphatic formality.
term of address for a man
a title used before the name of knight or baronet
Sir is a formal English honourific address for men, derived from Sire in the High Middle Ages. Traditionally, as governed by law and custom, is used for men titled as knights, i.e., of orders of chivalry, and later also applied to baronets and other offices.