The point in the sky directly above the North Pole of the Earth. As the Earth turns around its axis of rotation, the sky appears to turn, in the opposite direction, about an axis through the North and South Celestial Poles.
From any place in the Northern Hemisphere, there is a point in the northern sky around which the stars appear to rotate. It is currently near Polaris, the Pole Star. There is an equivalent point in the southern hemisphere, although there is no significantly bright star to mark it.