Source : Webster's Revised Unabridged Dictionary (1913)

Lantern \Lan"tern\, n. [F. lanterne, L. lanterna, laterna, from
   Gr. ? light, torch. See {Lamp}.]
   1. Something inclosing a light, and protecting it from wind,
      rain, etc.; -- sometimes portable, as a closed vessel or
      case of horn, perforated tin, glass, oiled paper, or other
      material, having a lamp or candle within; sometimes fixed,
      as the glazed inclosure of a street light, or of a
      lighthouse light.

   2. (Arch.)
      (a) An open structure of light material set upon a roof,
          to give light and air to the interior.
      (b) A cage or open chamber of rich architecture, open
          below into the building or tower which it crowns.
      (c) A smaller and secondary cupola crowning a larger one,
          for ornament, or to admit light; such as the lantern
          of the cupola of the Capitol at Washington, or that of
          the Florence cathedral.

   3. (Mach.) A lantern pinion or trundle wheel. See {Lantern
      pinion} (below).

   4. (Steam Engine) A kind of cage inserted in a stuffing box
      and surrounding a piston rod, to separate the packing into
      two parts and form a chamber between for the reception of
      steam, etc.; -- called also {lantern brass}.

   5. (Founding) A perforated barrel to form a core upon.

   6. (Zo["o]l.) See {Aristotle's lantern}.

   Note: Fig. 1 represents a hand lantern; fig. 2, an arm
         lantern; fig. 3, a breast lantern; -- so named from the
         positions in which they are carried.

   {Dark lantern}, a lantern with a single opening, which may be
      closed so as to conceal the light; -- called also
      {bull's-eye}.

   {Lantern fly}, {Lantern carrier} (Zo["o]l.), any one of
      several species of large, handsome, hemipterous insects of
      the genera {Laternaria}, {Fulgora}, and allies, of the
      family {Fulgorid[ae]}. The largest species is {Laternaria
      phosphorea} of Brazil. The head of some species has been
      supposed to be phosphorescent.

   {Lantern jaws}, long, thin jaws; hence, a thin visage.

   {Lantern pinion}, {Lantern wheel} (Mach.), a kind of pinion
      or wheel having cylindrical bars or trundles, instead of
      teeth, inserted at their ends in two parallel disks or
      plates; -- so called as resembling a lantern in shape; --
      called also {wallower}, or {trundle}.

   {Lantern shell} (Zo["o]l.), any translucent, marine, bivalve
      shell of the genus {Anatina}, and allied genera.

   {Magic lantern}, an optical instrument consisting of a case
      inclosing a light, and having suitable lenses in a lateral
      tube, for throwing upon a screen, in a darkened room or
      the like, greatly magnified pictures from slides placed in
      the focus of the outer lens.

Dark \Dark\ (d[aum]rk), a. [OE. dark, derk, deork, AS. dearc,
   deorc; cf. Gael. & Ir. dorch, dorcha, dark, black, dusky.]
   1. Destitute, or partially destitute, of light; not
      receiving, reflecting, or radiating light; wholly or
      partially black, or of some deep shade of color; not
      light-colored; as, a dark room; a dark day; dark cloth;
      dark paint; a dark complexion.

            O dark, dark, dark, amid the blaze of noon,
            Irrecoverably dark, total eclipse Without all hope
            of day!                               --Milton.

            In the dark and silent grave.         --Sir W.
                                                  Raleigh.

   2. Not clear to the understanding; not easily seen through;
      obscure; mysterious; hidden.

            The dark problems of existence.       --Shairp.

            What may seem dark at the first, will afterward be
            found more plain.                     --Hooker.

            What's your dark meaning, mouse, of this light word?
                                                  --Shak.

   3. Destitute of knowledge and culture; in moral or
      intellectual darkness; unrefined; ignorant.

            The age wherein he lived was dark, but he Could not
            want light who taught the world to see. --Denhan.

            The tenth century used to be reckoned by medi[ae]val
            historians as the darkest part of this intellectual
            night.                                --Hallam.

   4. Evincing black or foul traits of character; vile; wicked;
      atrocious; as, a dark villain; a dark deed.

            Left him at large to his own dark designs. --Milton.

   5. Foreboding evil; gloomy; jealous; suspicious.

            More dark and dark our woes.          --Shak.

            A deep melancholy took possesion of him, and gave a
            dark tinge to all his views of human nature.
                                                  --Macaulay.

            There is, in every true woman-s heart, a spark of
            heavenly fire, which beams and blazes in the dark
            hour of adversity.                    --W. Irving.

   6. Deprived of sight; blind. [Obs.]

            He was, I think, at this time quite dark, and so had
            been for some years.                  --Evelyn.

   Note: Dark is sometimes used to qualify another adjective;
         as, dark blue, dark green, and sometimes it forms the
         first part of a compound; as, dark-haired, dark-eyed,
         dark-colored, dark-seated, dark-working.

   {A dark horse}, in racing or politics, a horse or a candidate
      whose chances of success are not known, and whose
      capabilities have not been made the subject of general
      comment or of wagers. [Colloq.]

   {Dark house}, {Dark room}, a house or room in which madmen
      were confined. [Obs.] --Shak.

   {Dark lantern}. See {Lantern}. -- The

   {Dark Ages}, a period of stagnation and obscurity in
      literature and art, lasting, according to Hallam, nearly
      1000 years, from about 500 to about 1500 A. D.. See
      {Middle Ages}, under {Middle}.

   {The Dark and Bloody Ground}, a phrase applied to the State
      of Kentucky, and said to be the significance of its name,
      in allusion to the frequent wars that were waged there
      between Indians.

   {The dark day}, a day (May 19, 1780) when a remarkable and
      unexplained darkness extended over all New England.

   {To keep dark}, to reveal nothing. [Low]

Source : WordNet®

dark lantern
     n : a lantern with a sliding panel to conceal the light