BANG file

A BANG file (balanced and nested grid file) is a point access method which divides space into a nonperiodic grid. Each spatial dimension is divided by a linear hash. Cells may intersect, and points may be distributed between them.

Another meaning
In some early ICL mainframe computers, a bang file was a temporary data storage file whose name began with a ! character (which is sometimes nicknamed "bang") and automatically deleted when the run or user session ended.