What is the relativity of coordinate, rest, movement and speed?

A relative coordinate is a measured coordinate relative to some previously adopted system. The relative coordinate of rest – if the body in the relative system moves with the same speed as the adopted coordinate system itself. Displacement – if the body moves with a different speed or a different vector relative to the system. Relative speed – any speed that is different or equal to the speed of the system. To imagine all this, imagine a person who is standing, walking along a moving train carriage.