Homography

Webster's Dictionary of the English Language

·noun That method of spelling in which every sound is represented by a single character, which indicates that sound and no other.

II. Homography ·noun 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.