The use of two or more monitors on a computer. Desktop computers are always capable of extended desktop mode, but require additional hardware (see
dual monitor). However, the term often refers to laptop computers, which have a VGA or DVI port that can connect to a desktop monitor or to a data projector for classroom and theater presentations.
The second monitor can display the same image as the first (mirrored mode), or it can be set to extended desktop mode, in which both the internal and external monitors act as one large screen.