This document defines common terms used to describe points, lines, and planes in geometry. It defines a point as having no dimensions, a line as being one-dimensional, and a plane as being two-dimensional. Points are represented by capital letters, lines by two capital letters with a line above, and planes by the word "Plane" followed by a capital letter or three capital letters. Collinear points lie on the same line and coplanar points lie in the same plane. A line segment connects two endpoints and a ray extends from an initial point in one direction. Opposite rays intersect to form a line.