The Collaborative International Dictionary of English v.0.48:

Sgraffito \Sgraf*fi"to\, a. [It.] (Paint.)
   Scratched; -- said of decorative painting of a certain style,
   in which a white overland surface is cut or scratched
   through, so as to form the design from a dark ground
   underneath.
   [1913 Webster]

WordNet (r) 3.0 (2006):

sgraffito
    n 1: a ceramic or mural decoration made by scratching off a
         surface layer to reveal the ground