The Collaborative International Dictionary of English v.0.48:

Gong \Gong\, n. [AS. gong, gang, a going, passage, drain. See
   Gang.]
   A privy or jakes. [Obs.] --Chaucer.
   [1913 Webster]

   Gong farmer, Gong man, a cleaner of privies. [Obs.]
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Gong \Gong\, n.
   1. [Malayan (Jav.) g[=o]ng.] An instrument, first used in the
      East, made of an alloy of copper and tin, shaped like a
      disk with upturned rim, and producing, when struck, a
      harsh and resounding noise.
      [1913 Webster]

            O'er distant deserts sounds the Tartar gong.
                                                  --Longfellow.
      [1913 Webster]

   2. (Mach.) A flat saucerlike bell, rung by striking it with a
      small hammer which is connected with it by various
      mechanical devices; a stationary bell, used to sound calls
      or alarms; -- called also gong bell.
      [1913 Webster]

   Gong metal, an alloy (78 parts of copper, 22 of tin), from
      which Oriental gongs are made.
      [1913 Webster]

WordNet (r) 3.0 (2006):

gong
    n 1: a percussion instrument consisting of a metal plate that is
         struck with a softheaded drumstick [syn: gong, tam-tam]
    2: a percussion instrument consisting of a set of tuned bells
       that are struck with a hammer; used as an orchestral
       instrument [syn: chime, bell, gong]
    v 1: sound a gong

Moby Thesaurus II by Grady Ward, 1.0:

77 Moby Thesaurus words for "gong":
   battery, bell, bells, bones, castanets, celesta, chime, chimes,
   chink, church bell, clang, clangor, clank, clapper, clappers,
   clink, cowbell, crash cymbal, cymbals, ding, dingdong, dinner bell,
   dinner gong, dong, doorbell, finger cymbals, fire bell, gamelan,
   glockenspiel, gong bell, hand bell, handbells, idiophone, jangle,
   jingle, jingle bell, jinglejangle, knell, lyra, maraca, marimba,
   metallophone, orchestral bells, passing bell, peal, percussion,
   percussion instrument, percussions, percussive, rattle,
   rattlebones, ring, ring changes, sacring bell, sheepbell, sizzler,
   sleigh bell, snappers, sound, sound a knell, tam-tam,
   telephone bell, ting, tingle, tink, tinkle, tintinnabula,
   tintinnabulate, tintinnabulum, toll, tongue, tonitruone, triangle,
   tubular bells, vibes, vibraphone, xylophone