A set of keys on a terminal keyboard or keypad that the user can define in a request to allow the terminal operator to communicate with the application program at run time.; 終端鍵盤或小鍵盤上的一組鍵,用戶在需要時(shí)能定義它們,以允許終端操作員 在運(yùn)行時(shí)與應(yīng)用程序通信。