Source : Webster's Revised Unabridged Dictionary (1913)

Cubism \Cu"bism\ (k[=u]"b[i^]z'm), n. (Painting)
   A movement or phase in post-impressionism (which see, below).
   -- {Cu"bist}, n.

Source : WordNet®

cubism
     n : an artistic movement in France beginning in 1907 that
         featured surfaces of geometrical planes