Source : Webster's Revised Unabridged Dictionary (1913)

Frost \Frost\, v. t. [imp. & p. p. {Frostted}; p. pr. & vb. n.
   {Frosting}.]
   1. To injure by frost; to freeze, as plants.

   2. To cover with hoarfrost; to produce a surface resembling
      frost upon, as upon cake, metals, or glass.

            While with a hoary light she frosts the ground.
                                                  --Wordsworth.

   3. To roughen or sharpen, as the nail heads or calks of
      horseshoes, so as to fit them for frosty weather.

Frosting \Frost"ing\, n.
   1. A composition of sugar and beaten egg, used to cover or
      ornament cake, pudding, etc.

   2. A lusterless finish of metal or glass; the process of
      producing such a finish.

Source : WordNet®

frosting
     n : a flavored sugar topping used to coat and decorate cakes
         [syn: {icing}, {ice}]