Sir/(سيد)

A man of social authority and dignity; a lord; a master; a gentleman; -- in this sense usually spelled sire. A title prefixed to the Christian name of a knight or a baronet. An English rendering of the LAtin Dominus, the academical title of a bachelor of arts; -- formerly colloquially, and sometimes contemptuously, applied to the clergy. 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.

Noun

A man of a higher rank or position. A respectful term of address to a man of higher rank or position, particularly: A respectful term of address to an adult male (often older), especially if his name or proper title is unknown.

Verb

To address (someone) using "sir".