ˈsterēəˌskōp, ˈstir- noun
Etymology: stere- + -scope
: an optical instrument for obtaining from two pictures (as photographs made for the purpose from points of view typically corresponding to the position of the two eyes) a single three-dimensional image by means of two lenses used one with each eye and set sometimes in conjunction with mirrors to deflect rays coming from corresponding points in the two pictures in such a manner as to produce the effect of originating at a single point