The Free On-line Dictionary of Computing (18 March 2015):
(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 IBMThinkPad 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
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
"TrackPoint" and "Trackpoint" are IBM trademarks.
[INTERACT'90, North Holland Pub Co, pp. 700-706].