Center of gravity
In common usage, center of gravity means the dominant theme or central point of something. Physically, when an object is suspended from a point in the object and the vector of the suspending force passes through the center of gravity of the object the object hangs in equilibrium.
In the terms of the Fourth Way, the center of gravity of a person relates to the person's type – i.e. 1, moving center; 2, emotional center; or 3, thinking center dominated. Likewise, a school can have a center of gravity. Social movements and cultures can have a center of gravity.