Source : Webster's Revised Unabridged Dictionary (1913)

Wash \Wash\, n.
   1. [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.

   2. The dry bed of an intermittent stream, sometimes at the
      bottom of a ca[~n]on; as, the Amargosa wash, Diamond wash;
      -- called also {dry wash}. [Western U. S.]

   3. (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.

Source : WordNet®

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