As kev say's basicly just the smoothing process of stone tiles etc etc....
This might help as well
Honed or Polished?
The images give a representation of the difference between a honed finish and a polished finish. The stone is identical, it's just the finish that differs.
The stone on the left hand side has been honed, this means it is ground flat by a mechanical process and left with a matt/satin finish - if it were paint it would be described as eggshell.
The stone on the right has been honed and then polished, it is machined for a longer period of time using finer abrasives until the surface is highly shiney and reflective. - if it were a paint it would be described as high gloss.