The Collaborative International Dictionary of English v.0.48:

Wash \Wash\, n.
   1. The act of washing; an ablution; a cleansing, wetting, or
      dashing with water; hence, a quantity, as of clothes,
      washed at once.
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   2. A piece of ground washed by the action of a sea or river,
      or sometimes covered and sometimes left dry; the
      shallowest part of a river, or arm of the sea; also, a
      bog; a marsh; a fen; as, the washes in Lincolnshire. "The
      Wash of Edmonton so gay." --Cowper.
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            These Lincoln washes have devoured them. --Shak.
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   3. Substances collected and deposited by the action of water;
      as, the wash of a sewer, of a river, etc.
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            The wash of pastures, fields, commons, and roads,
            where rain water hath a long time settled.
                                                  --Mortimer.
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   4. Waste liquid, the refuse of food, the collection from
      washed dishes, etc., from a kitchen, often used as food
      for pigs. --Shak.
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   5. (Distilling)
      (a) The fermented wort before the spirit is extracted.
      (b) A mixture of dunder, molasses, water, and scummings,
          used in the West Indies for distillation. --B.
          Edwards.
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   6. That with which anything is washed, or wetted, smeared,
      tinted, etc., upon the surface. Specifically:
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      (a) A liquid cosmetic for the complexion.
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      (b) A liquid dentifrice.
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      (c) A liquid preparation for the hair; as, a hair wash.
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      (d) A medical preparation in a liquid form for external
          application; a lotion.
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      (e) (Painting) A thin coat of color, esp. water color.
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      (j) A thin coat of metal applied in a liquid form on any
          object, for beauty or preservation; -- called also
          washing.
          [1913 Webster +PJC]

   7. (Naut.)
      (a) The blade of an oar, or the thin part which enters the
          water.
      (b) The backward current or disturbed water caused by the
          action of oars, or of a steamer's screw or paddles,
          etc.
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   8. The flow, swash, or breaking of a body of water, as a
      wave; also, the sound of it.
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   9. Ten strikes, or bushels, of oysters. [Prov. Eng.]
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   10. [Western U. S.] (Geol.)
       (a) Gravel and other rock d['e]bris transported and
           deposited by running water; coarse alluvium.
       (b) An alluvial cone formed by a stream at the base of a
           mountain.
           [Webster 1913 Suppl.]

   11. The dry bed of an intermittent stream, sometimes at the
       bottom of a canyon; as, the Amargosa wash, Diamond wash;
       -- called also dry wash. [Western U. S.]
       [Webster 1913 Suppl.]

   12. (Arch.) The upper surface of a member or material when
       given a slope to shed water. Hence, a structure or
       receptacle shaped so as to receive and carry off water,
       as a carriage wash in a stable.
       [Webster 1913 Suppl.]

   13. an action or situation in which the gains and losses are
       equal, or closely compensate each other.
       [PJC]

   14. (Aeronautics) the disturbance of the air left behind in
       the wake of a moving airplane or one of its parts.
       [PJC]

   Wash ball, a ball of soap to be used in washing the hands
      or face. --Swift.

   Wash barrel (Fisheries), a barrel nearly full of split
      mackerel, loosely put in, and afterward filled with salt
      water in order to soak the blood from the fish before
      salting.

   Wash bottle. (Chem.)
       (a) A bottle partially filled with some liquid through
           which gases are passed for the purpose of purifying
           them, especially by removing soluble constituents.
       (b) A washing bottle. See under Washing.

   Wash gilding. See Water gilding.

   Wash leather, split sheepskin dressed with oil, in
      imitation of chamois, or shammy, and used for dusting,
      cleaning glass or plate, etc.; also, alumed, or buff,
      leather for soldiers' belts.
      [1913 Webster]

WordNet (r) 3.0 (2006):

dry wash
    n 1: the dry bed of an intermittent stream (as at the bottom of
         a canyon) [syn: wash, dry wash]