Paul, an axis is the geometric line around which a body , or a vector, or a magnetic field, anything! rotates. A body or mass may naturally prefer to rotate around an axis that is in line with its centre of gravity. But such does not define the meaning of an axis. An axis is a geometric term around which a rotation can occur. An out of balance rotation is common. And rotation is indeed a progressive radial orientation to this axis. In simple terms it means a radian progressing through 360 degrees around a central axis. I must agree that "orientation" can refer to a radian vectors direction from a centre . Allen, you will never find me having said anything contradicting your definition anywhere. You let your obstropolism blind you to the perfection of my theoretical applications of this principle.. Philip.