Pole. Earth is constantly rotating (spinning) on an imaginary line called an axis. The axis passes through the center of Earth and ends at either pole. The north end of the axis is approximately at the North Pole, 90 degrees north of the equator. The South Pole is approximately at the south end of the axis, 90 degrees south of the equator.
The term pole may be used to describe such a point on any revolving sphere. For example, celestial pole refers to a point in the heavens around which the stars seem to revolve. A bright star nearest the north celestial pole is called the North Star, or sometimes the polestar.
The North Pole and the South Pole are called Earth’s geographic poles. In addition to these poles, Earth has north and south magnetic poles, the farthest points on Earth in the directions of magnetic north and south. Earth’s magnetic field is generated by the motions of liquid metal in the planet’s core, and it varies constantly. For this reason, the north and south magnetic poles may wander hundreds or even thousands of miles or kilometers from the planet’s geographic poles. 
In physics, the word pole means the point where magnetic lines of force appear to originate. Magnetic poles that are unlike attract each other, and those that are alike repel each other.
See also Magnetism; Navigation; North Pole; South Pole.
