Source : Webster's Revised Unabridged Dictionary (1913)

Grinder \Grind"er\, n.
   1. One who, or that which, grinds.

   2. One of the double teeth, used to grind or masticate the
      food; a molar.

   3. (Zo["o]l.) The restless flycatcher ({Seisura inquieta}) of
      Australia; -- called also {restless thrush} and {volatile
      thrush}. It makes a noise like a scissors grinder, to
      which the name alludes.