A rotation is a                           circular movement
of an object                              around a center (or point)
                                                      of rotation.
A three-dimensional
object can always be                                                rotated around
                                                       an                         infinite                             number of
imaginary                                          lines
                                   called rotation axes                                   (/ˈæksiːz/ AK-seez).
                 If the axis passes                                               through the body's
                                        center of mass,
then the                                                            bo­dy is said to
rotate upon
itself, or spin.                                    A rotation
                                                   about an external
point, e.g. the Earth
             about the Sun,                     is called                                 a revolution
or orbital
                          revolution, typically                                              when
         it is                         produced by gravity.                                    The axis is called
                                 a pole.