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]

The Collaborative International Dictionary of English v.0.48:

Tallow \Tal"low\, n. [OE. taluh, talugh; akin to OD. talgh, D.
   talk, G., Dan. and Sw. talg, Icel. t[=o]lgr, t[=o]lg,
   t[=o]lk; and perhaps to Goth. tulgus firm.]
   1. The suet or fat of animals of the sheep and ox kinds,
      separated from membranous and fibrous matter by melting.
      [1913 Webster]

   Note: The solid consistency of tallow is due to the large
         amount of stearin it contains. See Fat.
         [1913 Webster]

   2. The fat of some other animals, or the fat obtained from
      certain plants, or from other sources, resembling the fat
      of animals of the sheep and ox kinds.
      [1913 Webster]

   Tallow candle, a candle made of tallow.

   Tallow catch, a keech. See Keech. [Obs.]

   Tallow chandler, one whose occupation is to make, or to
      sell, tallow candles.

   Tallow chandlery, the trade of a tallow chandler; also, the
      place where his business is carried on.

   Tallow tree (Bot.), a tree (Stillingia sebifera) growing
      in China, the seeds of which are covered with a substance
      which resembles tallow and is applied to the same
      purposes.
      [1913 Webster]

WordNet (r) 3.0 (2006):

tallow
    n 1: obtained from suet and used in making soap, candles and
         lubricants

Moby Thesaurus II by Grady Ward, 1.0:

19 Moby Thesaurus words for "tallow":
   animal oil, cerate, drying oil, essential oil, ester, fat,
   fatty oil, fixed oil, grease, hydrogenated fat, lipid, mineral oil,
   oil, oleum, polyunsaturated fat, sebum, unsaturated fat,
   vegetable oil, volatile oil