The Collaborative International Dictionary of English v.0.48:

Tallow \Tal"low\, v. t. [imp. & p. p. Tallowed; p. pr. & vb.
   n. Tallowing.]
   1. To grease or smear with tallow.
      [1913 Webster]

   2. To cause to have a large quantity of tallow; to fatten;
      as, tallow sheep.
      [1913 Webster]