Grand Geometrician
the Great Architect of the Universe, who formed humans as rough stones to be worked into perfect blocks for the cosmic Temple
G
The most common is that the "G" stands for God. Another is that it stands for Geometry, and is to remind Masons that Geometry and Freemasonry are synonymous terms described as being the "noblest of sciences", and "the basis upon which the superstructure of Freemasonry and everything in existence in the entire universe is erected. In this context, it can also stand for Great Architect of the Universe