Chording means pushing several keys or buttons simultaneously to achieve a result.
For example, in the Unix graphical user interface (known as X11), the middle button is used to paste text.
TipTapSpeech an application for the iPhone and iPad is a chord-based text entry solution for touch screen computing.
ComboKey also allows one-hand typing with the hand holding the device, generating combinations by occasional swipes to other keys.
Douglas Engelbart, Cherif Algreatly, Valerie Landau, Robert Stephenson, Evan Schaffer, and Eric Matsuno filed a patent in 2010 for a chorded solution for multitouch screens.