from The Century Dictionary.
- noun A form of grinding-apparatus or -mill for ores or similar material, in which a heavy disk or wheel runs in a circular path upon its edge in a pan or mortar. By its weight and the sliding motion of its edge as it revolves, it comminutes the material.
Sorry, no etymologies found.
The nib, coarse or finely ground, is mixed with the sugar in a kind of edge-runner or grinding-mixer, called a _mélangeur_.