crown lens(n = noun.artifact) - a lens made of optical crown glass;
is a kind of lens, lens system, lense

achromatic lens, anastigmatic lens, british crown, camera lens, closeup lens, compound lens, concave lens, contact lens, converging lens, convex lens, counsel to the crown, crown, crown beard, crown colony, crown daisy, crown fire, crown gall, crown glass, crown imperial, crown jewel, crown jewels, crown land, crown monkey, crown of thorns, crown office, crown prince, crown princess, crown roast, crown saw, crown side, crown vetch, crown wart, crown wheel, crystalline lens, diverging lens, electron lens, field lens, fisheye lens, fresnel lens, genus lens, golden crown beard, half crown, intraocular lens, jacket crown, lens, lens cap, lens capsule, lens cover, lens culinaris, lens implant, lens maker, lens system, macro lens, nero's crown, object lens, objective lens, optical crown, optical crown glass, optical lens, pinion and crown wheel, portrait lens, telephoto lens, triple crown, wide-angle lens, zoom lens