The Collaborative International Dictionary of English v.0.48:

Grid \Grid\ (gr[i^]d), n.
   1. A grating of thin parallel bars, similar to a gridiron.
      [1913 Webster]

   2. (Elec.) A plate or sheet of lead with perforations, or
      other irregularities of surface, by which the active
      material of a secondary battery or accumulator is
      supported.
      [Webster 1913 Suppl.]

   3. (Electronics) a mesh or coil of fine wire in an electron
      tube, connected to the circuit so as to regulate the
      current passing through the tube.
      [PJC]

   4. any network of crossing horizontal and vertical lines; --
      they are used, for example, as reference coordinates to
      locate objects or places on a map.
      [PJC]

   5. anything resembling a grid[4], as the Manhattan street
      grid. See also gridlock.
      [PJC]

   6. a network of connected conductors for distributing
      electrical power, especially one using high-tension lines
      for wide geographic distribution of power; as, the
      Northeast power grid.
      [PJC]

   7. (Football) the gridiron.
      [PJC]

WordNet (r) 3.0 (2006):

grid
    n 1: a pattern of regularly spaced horizontal and vertical lines
    2: a system of high tension cables by which electrical power is
       distributed throughout a region [syn: power system, power
       grid, grid]
    3: a perforated or corrugated metal plate used in a storage
       battery as a conductor and support for the active material
       [syn: grid, storage-battery grid]
    4: an electrode placed between the cathode and anode of a vacuum
       tube to control the flow of electrons through the tube [syn:
       grid, control grid]
    5: a cooking utensil of parallel metal bars; used to grill fish
       or meat [syn: grid, gridiron]

Moby Thesaurus II by Grady Ward, 1.0:

131 Moby Thesaurus words for "grid":
   L, R, acting area, andiron, apron, apron stage, arabesque,
   backstage, band shell, bandstand, basketry, basketwork, black spot,
   bloom, blooping, board, bridge, cancellation, chain, coal tongs,
   coulisse, crane, crook, cross-hatching, crossing-out, damper,
   definition, dock, dressing room, filigree, fire hook, fire tongs,
   firedog, flare, flies, fly floor, fly gallery, forestage, fret,
   fretwork, fringe area, ghost, granulation, grate, grating,
   greenroom, griddle, gridiron, grill, grille, griller, grillwork,
   hachure, hard shadow, hatching, image, interlacement, intertexture,
   intertwinement, lace, lacery, lacework, lacing, lattice,
   latticework, lifter, lightboard, mesh, meshes, meshwork,
   multiple image, net, netting, network, noise, orchestra,
   orchestra pit, performing area, picture, picture noise,
   picture shifts, pit, plexure, plexus, poker, pothook, proscenium,
   proscenium stage, raddle, rain, reticle, reticulation, reticule,
   reticulum, riddle, rolling, salamander, scanning pattern,
   scintillation, screen, screening, shading, shell, sieve, snow,
   snowstorm, spit, stage, stage left, stage right, switchboard,
   texture, the boards, tissue, tongs, tracery, trellis, trelliswork,
   tripod, trivet, turnspit, wattle, weave, weaving, web, webbing,
   webwork, weft, wicker, wickerwork, wings