That area would be known as the origin of a coordinate system. With the coordinate system, shapes can be transformed. A transform creates a coordinate system that is positioned, rotated, and scaled relative to parent coordinate system. Shapes built in a new coordinate system are portioned, rotated, and scaled along with it. The Transform group node creates a group with its own coordinate system.
Rotation orients a coordinate system about a rotation axis by a rotation angle.
Angles are measure in radians. All of the above techniques and formatting are the basic fundamentals to building a VRML world. Once you have an understanding for building shape nodes and visualizing a coordinate system, building a world becomes as simple as learning your ABC's. Below are lists of worlds that I've created. This is done by simply adding a Background Node.