Real Dictionary

gong
countable noun: A gong is a large, flat, circular piece of metal that you hit with a hammer to make a sound like a loud bell. Gongs are sometimes used as musical instruments, or to give a signal that it is time to do something.

gong in American English
a slightly convex metallic disk that gives a loud, resonant tone when struck: used as a signal, percussion instrument, etc.
intransitive verb: to sound as a gong does; ring, chime, or reverberate
noun: a large bronze disk, of Asian origin, having an upturned rim, that produces a vibrant, hollow tone when struck, usually with a stick or hammer that has a padded head

gong in British English
noun: a percussion instrument of indefinite pitch, consisting of a metal platelike disc struck with a soft-headed drumstick
verb: to sound a gong