A gong is a large percussion instrument that you play by hitting it with a mallet. Gongs make a resonant, echoing sound. In the classic game show "The Gong Show," amateur performers tried to impress judges who could end the act by banging a giant gong.
There are two types of gongs: one that makes a loud, crashing sound, and another that is actually tuned to a specific note. The crashing gong is sometimes also called a tam-tam. The oldest gongs were played in the early Han Dynasty in China, and gongs continue to be common in religious and secular Chinese music. Gong, named for the sound of a gong, comes from Malay.