S: (n) jeweler's glass (an optical instrument used by jewelers; has one or more lenses and is used to view features not readily seen)
S: (n) periscope (an optical instrument that provides a view of an otherwise obstructed field)
S: (n) projector (an optical instrument that projects an enlarged image onto a screen)
S: (n) sights (an optical instrument for aiding the eye in aiming, as on a firearm or surveying instrument)
S: (n) spectacles, specs, eyeglasses, glasses ((plural) optical instrument consisting of a frame that holds a pair of lenses for correcting defective vision)