parallax /ˈpærəˌlæks/ noun 1. an apparent change in the position of an object resulting from a change in position of the observer 2. an apparent shift in the position of an object, such as a star, caused by a change in the observer's position that provides a new line of sight. the parallax of nearby stars caused by observing them from opposite points in earth's orbit around the sun is used in estimating the stars' distance from earth through triangulation. very few art works in this book belong to me.All Rights Reserved