A monitor or a display is an electronic visual display for computers. The monitor comprises the display device, circurity and an enclosure. The display device in modern monitors is typically a thin film transistor liquid chrystal display thin film transistor liquid (TFT-LCD) thin panel, while older monitors used a cathode rade tube (CRT) about as deep as the screen size.

Originally, computer monitors were used for data procecing while television recevers were used for entertainment. From the 1980s onwards, computers (and their monitors) have been used for both data processing and entertainment, while televisions have implemented some computer functionality. The common aspect ratio of televisions, and then computer monitors, has also changed from 4:3 to 16:9.

History Early electronic computers were fitted with a panel of light bulbs where the state of each particular bulb would indicate the on/off state of a particular register bit inside the computer. This allowed the engineers operating the computer to monitor the internal state of the machine, so this panel of lights came to be known as the 'monitor'. As early monitors were only capable of displaying a very limited amount of information, and were very transient, they were rarely considered for programme output. Instead, a line printer was the primary output device, while the monitor was limited to keeping track of the programme's operation.

As technology developed it was realized that the output of a CRT display was more flexible than a panel of light bulbs and eventually, by giving control of what was displayed to the programme itself, the monitor itself became a powerful output device in its own right