noun
built-in variable; predefined variable
Computing term for a variable that is already defined by the system or environment, as opposed to one defined by the user.
このプログラミング言語では、定義済み変数を使ってシステム情報を取得できます。
In this programming language, you can get system information using built-in variables.
Compound of 定義済み (defined) + 変数 (variable). A straightforward technical term.