Source : Webster's Revised Unabridged Dictionary (1913)

Wash drawing \Wash drawing\ (Art)
   In water-color painting, work in, or a work done chiefly in,
   washes, as distinguished from that done in stipple, in body
   color, etc.

Source : WordNet®

wash drawing
     n : a watercolor made by applying a series of monochrome washes
         one over the other [syn: {wash}]