What is Z-axis?

The Z-axis is one of the three axes in a 3D coordinate system, along with the X-axis and Y-axis. It represents the depth dimension, meaning it defines how far a point extends forward or backward in space relative to a reference origin. In most graphical and mathematical models, the Z-axis is perpendicular to both the X-axis (horizontal) and Y-axis (vertical), completing the three-dimensional framework used to describe spatial positions.