Source : Webster's Revised Unabridged Dictionary (1913)

Washout \Wash"out`\, n.
   The washing out or away of earth, etc., especially of a
   portion of the bed of a road or railroad by a fall of rain or
   a freshet; also, a place, especially in the bed of a road or
   railroad, where the earth has been washed away.

Source : WordNet®

washout
     n 1: the channel or break produced by erosion of relatively soft
          soil by water; "it was several days after the storm
          before they could repair the washout and open the road"
     2: the erosive process of washing away soil or gravel by water
        (as from a roadway); "from the house they watched the
        washout of their newly seeded lawn by the water" [syn: {wash}]
     3: someone who is unsuccessful [syn: {flop}, {dud}]