The Collaborative International Dictionary of English v.0.48:

Grisaille \Gri"saille`\, n. [F., from gris gray.]
   1. (Fine Arts) Decorative painting in gray monochrome; --
      used in English especially for painted glass.
      [1913 Webster]

   2. A kind of French fancy dress goods. --Knight.
      [1913 Webster]

WordNet (r) 3.0 (2006):

grisaille
    n 1: chiaroscuro painting or stained glass etc., in shades of
         grey imitating the effect of relief