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

peanut gallery \pea"nut gal"lery\
   1. the cheapest seats in a theater, being typically those
      farthest from the stage, as in the uppermost balcony.
      pjc

   2. in a television show for children, the section where
      visiting children sit as guests during the performance.
      pjc

   3. hence: any group of children, or the chidren in a group of
      people; as, let's have no noise from the peanut gallery.
      colloq.
      pjc

[2] : WordNet (r) 2.0

peanut gallery
     n 1: figurative people whose criticisms are regarded as
          irrelevant or insignificant resembling uneducated
          people who throw peanuts on the stage to express
          displeasure with a performance; "he ignored complaints
          from the peanut gallery"
     2: rearmost or uppermost area in the balcony containing the
        least expensive seats syn: second balcony, family
        circle, upper balcony
see also:
second balcony family circle upper balcony 

[3] : Moby Thesaurus II by Grady Ward, 1.0

43 moby thesaurus words for "peanut gallery":
   texas tower, auditorium, balcony, beacon, belvedere, bleachers,
   box, box seat, bridge, conning tower, dress circle, fauteuil,
   gallery, gazebo, grandstand, lighthouse, loge, lookout, loophole,
   nigger heaven, observation post, observatory, orchestra,
   orchestra circle, outlook, overlook, paradise, parquet,
   parquet circle, parterre, peephole, pharos, pit, proscenium boxes,
   ringside, ringside seat, sighthole, stall, standing room,
   theatre stall, top gallery, tower, watchtower

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

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

Peanut >> P Words
Peanut, definition of term: Peanut
peanut_pag1.html

Peanut Butter >> P Words
Peanut Butter, definition of term: Peanut Butter
peanut+butter_pag1.html

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