external declaration
In programming, a declaration that tells the compiler about a variable or function defined in another file or module.
In C, you can call functions from other files using external declarations.
宣言 is a general declaration, while 外部宣言 specifically refers to an external declaration in programming.
Compound of 外部 (external) and 宣言 (declaration), a calque of the English computing term 'external declaration'.