An Etymological Dictionary of Astronomy and Astrophysics
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The point of the sky, north or south, where the projection of the Earth's axis of rotation intersects the → celestial sphere. They are at 90° relative to the → celestial equator. Because of → precession, the celestial poles describe a circle around the ecliptic's poles every 25,800 years.

→ celestial; → pole.

The point in the → northern hemisphere where the → rotation axis of Earth touches the → celestial sphere. The star → Polaris, also called the Pole Star, is located very near this point, at an angular separation of 42 degrees (about 1.4 lunar diameters).

→ north; → celestial; → pole.

The point in the → southern hemisphere where the → rotation axis of the Earth touches the → celestial sphere. In contrast to the → north celestial pole, no bright star is visible in that direction.

→ north; → celestial; → pole.

The direction of the Earth's instantaneous rotation pole. It differs from the pole due to the short time-scale (days or decades) variations called → nutation.

→ true; → celestial; → pole.