The Collaborative International Dictionary of English v.0.48:

Grille \Grille\, a. [F. See Grill, v. t.]
   A lattice or grating.
   [1913 Webster]

         The grille which formed part of the gate. --L.
                                                  Oliphant.
   [1913 Webster]

WordNet (r) 3.0 (2006):

grille
    n 1: small opening (like a window in a door) through which
         business can be transacted [syn: wicket, lattice,
         grille]
    2: grating that admits cooling air to car's radiator [syn:
       grille, radiator grille]
    3: a framework of metal bars used as a partition or a grate; "he
       cooked hamburgers on the grill" [syn: grill, grille,
       grillwork]

Moby Thesaurus II by Grady Ward, 1.0:

80 Moby Thesaurus words for "grille":
   arabesque, basketry, basketwork, bay, bay window, bow window,
   cancellation, casement, casement window, cross-hatching,
   crossing-out, fan window, fanlight, filigree, fret, fretwork,
   grate, grating, grid, gridiron, grillwork, hachure, hatching,
   interlacement, intertexture, intertwinement, lace, lacery,
   lacework, lacing, lancet window, lantern, lattice, latticework,
   light, louver window, mesh, meshes, meshwork, net, netting,
   network, oriel, pane, picture window, plexure, plexus, port,
   porthole, raddle, reticle, reticulation, reticule, reticulum,
   riddle, rose window, screen, screening, sieve, skylight, texture,
   tissue, tracery, transom, trellis, trelliswork, wattle, weave,
   weaving, web, webbing, webwork, weft, wicker, wickerwork, wicket,
   window, window bay, window glass, windowpane