I understand it to mean a number of different things. I believe structurally it described the distance from the main wing to the tail and how the inertial forced are thus created from this configuration. In more simple terms I take it to me how nice the aircraft feels to fly in terms of obedience in roll, pitch and yaw from inputs.
I suppose I am asking if the a/c is co operative or needs a fair bit of work on your part to do what you want it to aerodynamically.
Cheers