TrackPoint
<hardware> (Or "pointing stick", "nipple") A small knob found in the middle of some keyboards that works like a very short
isometric joystick.
Pressing it toward or away from you or from side to side moves the
pointer on the screen.
Ted Selker brought the concept of an in-keyboard pointing device to
IBM in September 1987.
TrackPoint was introduced in 1992 on the
IBM ThinkPad and later on some desktops.
It takes up virtually no extra room on the box or the work area and also requires minimal movement of the hands from the keyboard.
Many imitations of highly variable quality appeared.
Pointing sticks have also been used in many other
notebook brands, including TI,
HP, Compac, Dell, Toshiba (e.g. Portege 4000's "AccuPoint II"), and
AST (e.g. Ascentia 910N).
"TrackPoint" and "Trackpoint" are IBM trademarks.
(http://www.research.ibm.com/mathsci/cmc/trackpoint.htm).
[INTERACT'90, North Holland Pub Co, pp. 700-706].