What does "milling" mean?

Milling: The act or employment of grinding or passing through a mill; the process of fulling; the process of making a raised or intented edge upon coin, etc.; the process of dressing surfaces of various shapes with rotary cutters. See Mill. High milling, milling in which grain is reduced to flour by a succession of crackings, or of slight and partial crushings, alternately with sifting and sorting the product. -- Low milling, milling in which the reduction is effected in a single crushing or grinding. -- Milling cutter, a fluted, sharp-edged rotary cutter for dressing surfaces, as of metal, of various shapes. -- Milling machine, a machine tool for dressing surfaces by rotary cutters. -- Milling tool, a roller with indented edge or surface, for producing like indentations in metal by rolling pressure, as in turning; a knurling tool; a milling cutter.