Definition of king's english in English English dictionary
Especially in England, spoken or written English which is standard, characterized by grammatical correctness, proper usage of words and expressions, and (when spoken) formal British pronunciation
The O.E.D. is unlike any other dictionary. . . . It wants every word, all the lingo: idioms and euphemisms, sacred or profane, dead or alive, the King’s English or the street’s.
English speech or usage that is considered standard or accepted; Received Standard English. the King's English correct English, as it is spoken in Britain