standard language; standard variety
Refers to the codified standard form of a language used in official, educational, and media contexts. In Japanese contexts, it often specifically means the Tokyo-based standard Japanese.
At school, students are instructed to use standard language.
standard Japanese
When the context is clearly about Japanese, 標準語 is understood as the Tokyo-based standard Japanese, as opposed to regional dialects.
He spoke in standard Japanese, not Kansai dialect.
She never uses dialect and always speaks standard Japanese.
The teacher corrected the dialect sentence into standard Japanese.
The teacher explained the grammar in standard Japanese.
This book prints the dialect dialogue translated into standard Japanese.