Prismatic joint seen in 2-dimensional form, noting that the joint may only move in one direction. Bottom shows a sample piston cylinder cutout which utilizes a prismatic joint.
A prismatic joint provides a linear sliding movement between two bodies, and is often called a slider, as in the slider-crank linkage. A prismatic joint can be formed with a polygonal cross-section to resist rotation. See for example the dovetail joint and linear bearings.
The relative position of two bodies connected by a prismatic joint is defined by the amount of linear slide of one relative to the other one. This one parameter movement identifies this joint as a one degree of freedomkinematic pair.