The origin of the verb “to monitor” is the Latin word “monit” –meaning to warn. Thus, a monitor is basically someone or a device that watches over or listens to something. It could be a TV receiver viewing the output from a TV or video camera; or, an audio speaker used to hear what sound is being recorded; meaning that it is observing and maintaining surveillance over a period of time. This, in a way, is what the monitor for your computer is actually doing since it shows you on a screen what actions are being performed inside the computer.