1) A whiteboard is a non-electronic variation of the traditional "rewriteable" schoolroom blackboard, but is white instead of black and of a material that can be written on with colored markers (known as dry erase markers). Dry erase markers are easier to erase than the chalk used on a blackboard (which sometimes requires a wet rag for thorough erasing).
2) In electronic education technology and computer networks, an electronic whiteboard is one of several kinds of writeable presentation display systems that can be used in a classroom or videoconference. These whiteboards generally fall into one of three categories: standalone copy boards, where the content of the whiteboard can be scanned and printed out; peripheral boards, which transfer information in the form of digital files to an attached computer; and interactive boards, the most expensive and sophisticated option, which are like large touchscreen monitors that can be synchronized to an attached computer -- users can interact with the display, visit Web sites, and access databases directly from the board. Some peripheral boards can accommodate a projector that can be calibrated to the display, making them interactive. There are a number of add-on whiteboard digitizer products available, such as mimio and eBeam, that can be used to make traditional dry-erase whiteboards interactive.
3) In some groupware programs in which remote users teleconference from their PCs, a whiteboard is a space on the display in which one or more participants write or draw, using a mouse, keyboard, or other input device.