In mathematics and geometry, the Cartesian coordinate system is a coordinate system used to give the location of points on a plane by using two numbers for each point. It is also called the "rectangular coordinate system". The numbers are usually called the "x coordinate" and the "y coordinate". To find the coordinates of a point, two perpendicular lines, called "axes" (singular: "axis"), are drawn. The point where the axes meet is the coordinate origin, written (0, 0). The x coordinate gives the position of a point measured along the x axis, and the y coordinate gives the position along the y axis. Cartesian coordinates can be used in three dimensions (3D), by adding a third number, the "z coordinate". Each coordinate represents a dimension of space.