Source : Webster's Revised Unabridged Dictionary (1913)

Grist \Grist\, n. [AS. grist, fr. grindan. See {Grind}.]
   1. Ground corn; that which is ground at one time; as much
      grain as is carried to the mill at one time, or the meal
      it produces.

            Get grist to the mill to have plenty in store.
                                                  --Tusser. Q.

   2. Supply; provision. --Swift.

   3. In rope making, a given size of rope, common grist being a
      rope three inches in circumference, with twenty yarns in
      each of the three strands. --Knight.

   {All is grist that comes to his mill}, all that he has
      anything to do with is a source of profit. [Colloq.]

   {To bring grist to the maill}, to bring profitable business
      into one's hands; to be a source of profit. [Colloq.]
      --Ayliffe.

Source : WordNet®

grist
     n : grain intended to be or that has been ground