opengl stands for .....

which one is true? “opengl = open graphics language” or “opengl = open graphics library”?

Graphics Library

“Open” means that it can be used on other platforms instead of just on SGI machines.

I do not think that OpenGL is a language likes basic,c,java…
OpenGL isa set of API for several os.

I would say open does not stand for cross-platform availability, but it is open because it is controlled by ARB, and thus not by a single company.