Lens

• POS: Noun

CIDE DICTIONARY

Lens, n. [L. lens a lentil. So named from the resemblance in shape of a double convex lens to the seed of a lentil. Cf. Lentil.].

 A piece of glass, or other transparent substance, ground with two opposite regular surfaces, either both curved, or one curved and the other plane, and commonly used, either singly or combined, in optical instruments, for changing the direction of rays of light, and thus magnifying objects, or otherwise modifying vision. In practice, the curved surfaces are usually spherical, though rarely cylindrical, or of some other figure.  [1913 Webster]
" Of spherical lenses, there are six varieties, as shown in section in the figures herewith given: viz., a plano-concave; b double-concave; c plano-convex; d double-convex; e converging concavo-convex, or converging meniscus; f diverging concavo-convex, or diverging meniscus."  [1913 Webster]

Crossed lens (Opt.), a double-convex lens with one radius equal to six times the other. -- Crystalline lens. (Anat.) See Eye. -- Fresnel lens (Opt.), a compound lens formed by placing around a central convex lens rings of glass so curved as to have the same focus; used, especially in lighthouses, for concentrating light in a particular direction; -- so called from the inventor. -- Multiplying lens or Multiplying glass (Opt.), a lens one side of which is plane and the other convex, but made up of a number of plane faces inclined to one another, each of which presents a separate image of the object viewed through it, so that the object is, as it were, multiplied. -- Polyzonal lens. See Polyzonal.

OXFORD DICTIONARY

Lens, n.
1 a piece of a transparent substance with one or (usu.) both sides curved for concentrating or dispersing light-rays esp. in optical instruments.
2 a combination of lenses used in photography.
3 Anat. = crystalline lens.
4 Physics a device for focusing or otherwise modifying the direction of movement of light, sound, electrons, etc.

Derivative

lensed adj. lensless adj.

Etymology

L lens lentis lentil (from the similarity of shape)

THESAURUS

Lens

baby blues, banjo eyes, bright eyes, clear eyes, cornea, eye, eyeball, eyelid, goggle eyes, iris, lid, naked eye, nictitating membrane, oculus, optic, optic nerve, orb, organ of vision, peeper, popeyes, pupil, retina, saucer eyes, sclera, starry orbs, unaided eye, visual organ

ROGET THESAURUS

Lens

Optical Instruments

N optical instruments, lens, meniscus, magnifier, sunglass, magnifying glass, hand lens, microscope, megascope, tienoscope, spectacles, specs, glasses, barnacles, goggles, eyeglass, pince-nez, monocle, reading glasses, bifocals, contact lenses, soft lenses, hard lenses, sunglasses, shades, periscopic lens, telescope, glass, lorgnette, spyglass, opera glass, binocular, binoculars, field glass, burning glass, convex lens, concave lens, convexo-concave lens, coated lens, multiple lens, compound lens, lens system, telephoto lens, wide-angle lens, fish-eye lens, zoom lens, optical bench, astronomical telescope, reflecting telescope, reflector, refracting telescope, refractor, Newtonian telescope, folded-path telescope, finder telescope, chromatoscope, X-ray telescope, radiotelescope, phased-array telescope, Very Large Array radiotelescope, ultraviolet telescope, infrared telescope, star spectroscope, space telescope, altazimuth mount, equatorial mount, refractometer, circular dichroism spectrometer, interferometer, phase-contrast microscope, fluorescence microscope, dissecting microscope, electron microscope, transmission electron microscope, scanning electron microscope, SEM, scanning tunneling electron microscope, objective lens, eyepiece, barrel, platform, focusing knob, slide, slide glass, cover glass, counting chamber, illuminator, light source, polarizer, reticle, cross-hairs, light pipe, fiber optics mirror, reflector, speculum, looking- glass, pier-glass, cheval-glass, rear-view mirror, hand mirror, one-way mirror, magnifying mirror, fun house, prism, diffraction grating, beam splitter, half-wave plate, quarter-wave plate, camera lucida, camera obscura, magic lantern, stereopticon, chromatrope, thaumatrope, stereoscope, pseudoscope, polyscope, kaleidoscope, photometer, eriometer, actinometer, lucimeter, radiometer, ligth detector, photodiode, photomultiplier, photodiode array, photocell, X-ray diffractometer, goniometer, spectrometer, monochrometer, UV spectrometer, visible spectrometer, Infrared spectrometer, Fourier transform infrared spectrometer, recording spectrometer, densitometer, scanning densitometer, two-dimensional densitometer, abdominoscope, gastroscope, helioscope, polariscope, polemoscope, spectroscope, abdominoscopy, gastroscopy, microscopy, microscopist.