homography

n. 1. That method of spelling in which every sound is represented by a single character, which indicates that sound and no other. [ 1913 Webster ]

2. (Geom.) A relation between two figures, such that to any point of the one corresponds one and but one point in the other, and vise versa. Thus, a tangent line rolling on a circle cuts two fixed tangents of the circle in two sets of points that are homographic. [ 1913 Webster ]