Parallax

Parallax is the difference in the angular position of two stationary points relative to each other from different viewing positions. Nearby objects have a larger parallax than more distant objects when observed from different positions, so parallax can be used to determine distances.

As the viewpoint moves side to side, the objects in the distance appear to move more slowly than the objects close to the camera.

As the eyes of humans and other animals are in different positions on the head, they present different views simultaneously. This is the basis of stereopsis , the process by which the brain exploits the parallax due to the different views from the eye to gain depth perception and estimate distances to objects.

In a philosophic/geometric sense: An apparent change in the direction of an object, caused by a change in observational position that provides a new line of sight. The apparent displacement, or difference of position, of an object, as seen from two different stations, or points of view.