A slide potmeter is a potentiometer that has a linear movement direction as opposed to the rotational movement of the more commonly known potmeter.
Slide potmeters are commonly used in audio mixing panels and for various user inputs. They can also be used as linear position sensor (within their physical limitations).
The working principle, usage, and specifications are similar to those described for the more common rotational potmeter
Motorized versions of slide potmeters exist as well. They have a small built-in DC motor that can move the slider position. They can be used to a certain extent as linear actuators or for giving tactile feedback.