In a Cartesian coordinate system, the third dimension is typically associated with the Z-axis. In addition to the X and Y axes (representing the horizontal and vertical directions), the introduction of the Z-axis adds the third dimension, extending the coordinate system into three-dimensional space.
So, in a three-dimensional space, points are located using three coordinates: one along the X-axis, one along the Y-axis, and one along the Z-axis. The combination of these three coordinates specifies a unique position in 3D space. The X, Y, and Z axes are orthogonal to each other, forming a right-handed coordinate system commonly used in geometry, physics, computer graphics, and other fields.