A 3D world is described in terms of 3D Cartesian coordinates. In 3ds Max, the main coordinate space, used to describe the scene as a whole, is known as the coordinate system. When you create or transform an object, you can use other coordinate spaces, such as coordinates particular to a viewport, local to the object itself, or defined by a Grid object. See Reference Coordinate System for more details.
In What Is character studio? biped animation, the three most-used coordinate spaces are world, object, and body space . These are often used to control the biped's hands and feet.
Another coordinate system is used for the footstep gizmos themselves: a foot on a footstep is in that footstep's coordinate space. If the footstep is moved, the foot moves also. (A sliding footstep is a footstep that moves relative to the coordinate system of the corresponding footstep gizmo.)