<P> A rotation is simply a progressive radial orientation to a common point . That common point lies within the axis of that motion . The axis is 90 degrees perpendicular to the plane of the motion . If the axis of the rotation lies external of the body in question then the body is said to orbit . There is no fundamental difference between a `` rotation '' and an `` orbit '' and or `` spin '' . The key distinction is simply where the axis of the rotation lies , either within or outside of a body in question . This distinction can be demonstrated for both `` rigid '' and `` non rigid '' bodies . </P>
an object that moves around an external axis is said to be
orbit