Definition of: stereoscope

(ster′·ē·ə·skōp, stir′-) noun
An instrument for blending into one stereoscope two pictures of an object from slightly different points of view, so as to produce upon the eye the impression of relief and solidity. [<STEREO- + -SCOPE]
—ster′e·o·scop′ic (-skop′ik) or ·i·cal adjective
—ster′·e·o·scop′i·cal·ly adverb
STEREOSCOPE
Line of sight, Ll and Rr, of the eyes, combines the stereoscopes of points l and r at O. A card (at dotted line) shuts off two side stereoscopes otherwise seen along Rl at l and Lr at r.