The Collaborative International Dictionary of English v.0.48:

Lantern \Lan"tern\ (l[a^]n"t[~e]rn), n. [F. lanterne, L.
   lanterna, laterna, from Gr. lampth`r 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.
      [1913 Webster]

   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.
          [1913 Webster]

   3. (Mach.) A lantern pinion or trundle wheel. See Lantern
      pinion (below).
      [1913 Webster]

   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.
      [1913 Webster]

   5. (Founding) A perforated barrel to form a core upon.
      [1913 Webster]

   6. (Zool.) See Aristotle's lantern.
      [1913 Webster]

   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.
         [1913 Webster]

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

   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 (Zool.), 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.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Lantern \Lan"tern\, v. t. [imp. & p. p. Lanterned; p. pr. &
   vb. n. Lanterning.] [Cf. F. lanterner to hang at the lamp
   post, fr. lanterne. See Lantern.]
   To furnish with a lantern; as, to lantern a lighthouse.
   [1913 Webster]

WordNet (r) 3.0 (2006):

lantern
    n 1: light in a transparent protective case

Moby Thesaurus II by Grady Ward, 1.0:

103 Moby Thesaurus words for "lantern":
   antenna tower, barbican, bay, bay window, belfry, bell tower,
   bow window, campanile, candle, casement, casement window, ceiling,
   colossus, column, cupola, derrick, dome, eaves,
   electric light bulb, fan window, fanlight, fire, fire tower, flame,
   glim, grille, housetop, illuminant, illuminator, incandescent body,
   lamp, lancet window, lattice, light, light bulb, light source,
   lighthouse, louver window, luminant, luminary, martello,
   martello tower, mast, match, minaret, monument, moon, obelisk,
   observation tower, oriel, overhead, pagoda, pane, penthouse,
   picture window, pilaster, pillar, pinnacle, plafond, pole, port,
   porthole, pylon, pyramid, ridgepole, roof, roof garden, roof-deck,
   roofage, roofing, roofpole, rooftop, rooftree, rose window, shaft,
   shingles, skylight, skyscraper, slates, source of light, spire,
   standpipe, stars, steeple, stupa, sun, taper, television mast,
   tiles, top, tope, torch, tour, tower, transom, turret, water tower,
   wicket, windmill tower, window, window bay, window glass,
   windowpane