(1) In a remote control operation, a terminal window displays the screen of the remote machine it is controlling. See remote control software.
(2) For local or remote execution of a program, it is a window in a graphical interface that is used to display a command line. For example, in Unix/Linux environments, the terminal window is widely used by developers to perform myriad maintenance operations in local and remote computers; the same way the DOS command line is used in Windows. See command line.