Questions about how minecraft's coordinates system works

In minecraft, are the axis of the player and other mobs handled independently to that of the world?

A better summation of what I mean

I want to spawn particles to the player's left. In case one where the coordinates are rendered separately to the world. I could tell the game to spawn particles along the -z axis 

and then the particles would always spawn to the left of the player at the set distance of the z axis.

In the second case where the player coordinates are not handled separately  would I have to do some math to locate what is the player's left and then spawn the particle at that point?

Tldr : 

When I give coordinates relative to an entity. do they take into account the entity's X, Y, Z, Axis or is it handled via the World's X, Y, Z, Axis?