The Collaborative International Dictionary of English v.0.48:

Peat \Peat\ (p[=e]t), n. [Cf. Pet a fondling.]
   A small person; a pet; -- sometimes used contemptuously.
   [Obs.] --Shak.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Peat \Peat\, n. [Prob. for beat, prop., material used to make
   the fire burn better, fr. AS. b[=e]tan to better, mend (a
   fire), b[=o]t advantage. See Better, Boot advantage.]
   A substance of vegetable origin, consisting of roots and
   fibers, moss, etc., in various stages of decomposition, and
   found, as a kind of turf or bog, usually in low situations,
   where it is always more or less saturated with water. It is
   often dried and used for fuel.
   [1913 Webster]

   Peat bog, a bog containing peat; also, peat as it occurs in
      such places; peat moss.

   Peat moss.
   (a) The plants which, when decomposed, become peat.
   (b) A fen producing peat.
   (c) (Bot.) Moss of the genus Sphagnum, which often grows
       abundantly in boggy or peaty places.

   Peat reek, the reek or smoke of peat; hence, also, the
      peculiar flavor given to whisky by being distilled with
      peat as fuel. [Scot.]
      [1913 Webster]

WordNet (r) 3.0 (2006):

peat
    n 1: partially carbonized vegetable matter saturated with water;
         can be used as a fuel when dried

Moby Thesaurus II by Grady Ward, 1.0:

41 Moby Thesaurus words for "peat":
   alcohol, benzine, briquette, burnable, butane, carbon, charcoal,
   coal, coke, combustible, dope, ethane, ethanol, fireball, firing,
   flammable, flammable material, fuel, fuel additive, fuel dope, gas,
   gas carbon, gasoline, heptane, hexane, inflammable,
   inflammable material, isooctane, jet fuel, kerosene, methane,
   methanol, natural gas, octane, oil, paraffin, pentane, propane,
   propellant, rocket fuel, turf