OpenGL stands for Open Graphics Library. It was first introduced with a 1.0 release by SGI in 1992 and has since become the leading industry standard, multiple platform graphics library. OpenGL was significant because it did not require developers or hardware manufacurers to purchase licenses to include it in their implementations. The OpenGL standard is maintained and modified through the OpenGL Architecture Review Board (http://www.opengl.org/about/arb/).
Nowadays OpenGL has gained wide hardware support and is frequently used in games, artistic applictions, and CAD software. It is the most frequently used 3D graphics library on Linux due to its open standard.