Received Standard (English); (formerly) received speech; see received, adj. 1b.
A language variety of a country or other linguistic area which is by convention generally considered the most correct and acceptable form, esp…
(H. C. Wyld's name for) the variety of a language which is most widely accepted and used as a standard (standard, n. 23) in any specified country…
The conventional and standardized written variety of a given language (or occasionally a dialect).