PHIGS - technical definition

(Programmer's Hierarchical Interactive Graphics Standard) A graphics system and language used to create 2D and 3D images. Like the GKS standard, PHIGS is a device-independent interface between the application program and the graphics subsystem.

It manages graphics objects in a hierarchical manner so that a complete assembly can be specified with all of its subassemblies. It is a very comprehensive standard requiring high-performance workstations and host processing.