Meaning of SIR in English
Frequency: The word is one of the 1500 most common words in English.
People sometimes say ~ as a very formal and polite way of addressing a man whose name they do not know or a man of superior rank. For example, a shop assistant might address a male customer as ~.
Excuse me ~, but would you mind telling me what sort of car that is?...
Good afternoon to you, ~.
Sir is the title used in front of the name of a knight or baronet.
She introduced me to Sir Tobias and Lady Clarke.
You use the expression Dear ~ at the beginning of a formal letter or a business letter when you are writing to a man. You use Dear ~s when you are writing to an organization.
Dear Sir, Your letter of the 9th October has been referred to us.
Collins COBUILD. Толковый словарь английского языка для изучающих язык Коллинз COBUILD (международная база данных языков Бирмингемского университета) . 2012