Z-buffer
<graphics> An
array used to store the maximum Z
coordinate of any feature plotted at a given (X, Y) location on the screen, used for hidden line removal in a 2D rendering of a 3D scene.
The Z axis is perpendicular to the screen with values increasing toward the viewer so that any point whose Z coordinate is less than the corresponding Z-buffer value will be hidden behind some feature which has already been plotted.