Some text terminals support mouse clicks in the terminal window.
In a terminal emulator which is compatible with xterm, you
can use M-x xterm-mouse-mode to give Emacs control over simple
uses of the mouse—basically, only non-modified single clicks are
supported. Newer versions of xterm also support
mouse-tracking. The normal xterm mouse functionality for
such clicks is still available by holding down the SHIFT key
when you press the mouse button. Xterm Mouse mode is a global minor
mode (see Minor Modes), which is turned on by default if Emacs
detects at start time that the terminal supports it. Repeating the
command turns the mode off again.
In the console on GNU/Linux, you can use M-x gpm-mouse-mode to enable mouse support. You must have the gpm server installed and running on your system in order for this to work. Note that when this mode is enabled, you cannot use the mouse to transfer text between Emacs and other programs which use GPM. This is due to limitations in GPM and the Linux kernel.
See Mouse Usage on MS-DOS, for information about mouse support on MS-DOS.