Stationary object refers to an object that is not moving
A stationary object is an object that doesn't move.
0 velocity0 accelerationThe forces on the object are balanced: it is in equilibrium. (The forces are balanced on any object with 0 acceleration, even if it is moving.)
A stationary object used to gauge the movement of another object might be called the reference.
It's nice to be able to give directions to or from a point that is not easily moved by human or other means.