The Collaborative International Dictionary of English v.0.48:

Stereoscopy \Ste`re*os"co*py\, n.
   The art or science of using the stereoscope, or of
   constructing the instrument or the views used with it.
   [1913 Webster]

WordNet (r) 3.0 (2006):

stereoscopy
    n 1: three-dimensional vision produced by the fusion of two
         slightly different views of a scene on each retina [syn:
         stereoscopic vision, stereoscopy]