[1] : The Collaborative International Dictionary of English v.0.48

gallery \gal"lery\, n.; pl. galleries. f. galerie, it.
   galleria, fr. ll. galeria gallery, perh. orig., a festal
   hall, banquetting hall; cf. of. galerie a rejoicing, fr.
   galer to rejoice. cf. gallant, a.
   1. a long and narrow corridor, or place for walking; a
      connecting passageway, as between one room and another;
      also, a long hole or passage excavated by a boring or
      burrowing animal.
      1913 webster

   2. a room for the exhibition of works of art; as, a picture
      gallery; hence, also, a large or important collection of
      paintings, sculptures, etc.
      1913 webster

   3. a long and narrow platform attached to one or more sides
      of public hall or the interior of a church, and supported
      by brackets or columns; -- sometimes intended to be
      occupied by musicians or spectators, sometimes designed
      merely to increase the capacity of the hall.
      1913 webster

   4. naut. a frame, like a balcony, projecting from the stern
      or quarter of a ship, and hence called stern gallery or
      quarter gallery, -- seldom found in vessels built since
      1850.
      1913 webster

   5. fort. any communication which is covered overhead as
      well as at the sides. when prepared for defense, it is a
      defensive gallery.
      1913 webster

   6. mining a working drift or level.
      1913 webster

   whispering gallery. see under whispering.
      1913 webster
see also:
galleries gallant stern gallery quarter gallery defensive gallery whispering gallery 
whispering 

[2] : The Collaborative International Dictionary of English v.0.48

whispering \whis"pering\,
   a.  n. from whisper. v. t.
   1913 webster

   whispering gallery, or whispering dome, one of such a
      form that sounds produced in certain parts of it are
      concentrated by reflection from the walls to another part,
      so that whispers or feeble sounds are audible at a much
      greater distance than under ordinary circumstances. the
      dome of the u. s. capitol building is one example.
      1913 webster +pjc
see also:
whisper whispering gallery whispering dome 

[3] : WordNet (r) 2.0

whispering gallery
     n : a space beneath a dome or arch in which sounds produced at
         certain points are clearly audible at certain distant
         points syn: whispering dome
see also:
whispering dome 

Whispering >> W Words
Whispering, definition of term: Whispering
whispering_pag1.html

Gallery >> G Words
Gallery, definition of term: Gallery
gallery_pag1.html

Whispering Gall >> W Words
Whispering Gall, definition of term: Whispering Gall
whispering+gall_pag1.html

Rogues Gallery >> R Words
Rogues Gallery, definition of term: Rogues Gallery
rogues+gallery_pag1.html

Peanut Gallery >> P Words
Peanut Gallery, definition of term: Peanut Gallery
peanut+gallery_pag1.html