资料来源 : Webster's Revised Unabridged Dictionary (1913)

Whitening \Whit"en*ing\, n.
   1. The act or process of making or becoming white.

   2. That which is used to render white; whiting. [R.]

   {Whitening stone}, a sharpening and polishing stone used by
      cutlers; also, a finishing grindstone of fine texture.