Gong, a circular metal platelike percussion instrument, usually having a turned-down rim. In most forms it is struck in the centre with a felt- or leather-covered beater, producing a sound of either definite or indefinite pitch. Its vibrations issue from the centre, in contrast to bells, which vibrate principally at the rim. Gongs may have shallow or deep rims (kettle gongs) and may be bossed (knobbed in the centre) or unbossed. Rimless gongs occur occasionally.