VDU may refer to any of the following:
1. Short for visual display unit, VDU is an older British term describing any device used with computers to display text and images. For example, a flat-panel display and a projector are both examples of VDUs. However, VDU most commonly describes the CRT monitor, a now archaic standard replaced by flat-panel display methods like LED.
Early VDUs had a 13" screen size. By the mid-1990s, 15" and 17" VDU screen sizes became more common, with some 20" screen sizes starting to emerge on the market. By the early 2000s, flat-panel monitors with 15" and 17" screen sizes gained popularity and started replacing CRT monitors.
2. Short for video display unit, VDU is a computing device that allows for input by a user and output to a display, like a computer monitor. A VDU consists of a display device and a keyboard and could also include a mouse. In the United States, it is sometimes known as a video display terminal or VDT.
Two of the earliest VDUs were the Commodore PET and the Radio Shack TRS-80 Model 1, both developed in 1977. Other examples of early VDUs include the IBM 2260, Televideo 920C, and Texas Instruments Model 911. Each of these VDUs were a single unit with a built-in display screen and keyboard.