monitor

1. (computing) A device similar to a television set used as to give a graphical display of the output from a computer.Examples: "The information flashed up on the monitor."

2. (computing) A program for viewing and editing.Examples: "a machine code monitor"

3. (computing, dated) The command line interface of an operating system.dated

4. (Hong Kong, Singapore, archaic in British) A student leader in a class.Examples: "So, as she did not like the masters to be prying about the play-ground out of school, she chose from among the biggest and most trustworthy of her pupils five monitors, who had authority over the rest of the Boys, and kept the unruly ones in order."; "But it was not so—at least, not always—for though they fell out among themselves, they united their forces against the common enemy—the monitors!"; "He learned that a monitor should assist the teachers in distributing worksheets, maintaining class discipline, helping classmates in need and so on."Hong-KongSingaporearchaic

5. (nautical) A relatively small armored warship with only one or two turrets (but often carrying unusually large guns for a warship of its size), usually designed for shore bombardment or riverine warfare rather than open-ocean combat.

6. (engineering) A tool holder, as for a lathe, shaped like a low turret, and capable of being revolved on a vertical pivot so as to bring several tools successively into position.