Understanding Lorentz Transformations: Equations and Explanation

[ZedCar]

Just underneath the diagram of the 3 S-systems at the top of this webpage;
http://www.relativitycalculator.com/addition_relativistic_velocities.shtml

It gives equations for Lorentz transformation between S and S'

Does x' mean the distance between the origin of frame S' and the event as measured from the origin of frame S?

And does x mean the distance from the origin of the S frame to the event as measured from the origin of the S' frame?

Thank you.

 

[Doc Al]

x' is the position of the event as measured in the S' frame; x is the position of the event as measured in the S frame.