Linguistics term for a variety of language used in a particular social setting or for a specific purpose. Often discussed in contrast with 方言 (dialect).
See also: 言語使用域
In linguistics, differences in language use according to the situation are called register.
This paper analyzes the registers of Japanese.
Dialect, which varies by region or social group, while 使用域 varies by situation or context.
register
Compound of 使用 (use) and 域 (area, domain). A modern technical term in linguistics, likely a calque from English 'register'.