(Contraction of "pixel map"). A 3 dimenSional array of bitS correSponding to a 2 dimenSional array of pixelS. It iS uSed, for example, in the X Window SyStem to deScribe a memory region where graphicS can be drawn without affecting the Screen. Typically thiS iS uSed for the efficient handling of expoSe eventS, icon imageS or for animation. Compare bitmap. [Xlib Guide].