A slit drum or slit gong is a hollow percussion instrument. In spite of its often being called a drum, it is not a true drum because it lacks a drumhead, the membrane stretched across the top of a true drum). It is classed instead as an idiophone in which the entire instrument vibrates, usually carved or constructed from bamboo or wood, in the form of a mostly closed hollow chamber with one or more slits in it. It is played by striking near the edge of the slit. In some designs, the slit is a single straight line; in others, the slit is used to create one or more "tongues", achieved by cutting three sides of a rectangular shape and leaving the fourth side attached. Most slit drums have one slit, though two and three slits occur. Tongues of different areas or thicknesses will produce different pitches. Slit drums are used throughout Africa, Southeast Asia, and Oceania. In Africa such drums, strategically situated for optimal acoustic transmission, have been used for long-distance communication.

A percussion instrument is a musical instrument that is sounded by being struck or scraped by a beater including attached or enclosed beaters or rattles struck, scraped or rubbed by hand or struck against another similar instrument. Excluding zoomusicological instruments and the human voice, the percussion family is believed to include the oldest musical instruments. In spite of being a very common term to designate instruments, and to relate them to their players, the percussionists, percussion is not a systematic classificatory category of instruments, as described by the scientific field of organology. It is shown below that percussion instruments may belong to the organological classes of idiophone, membranophone, aerophone and chordophone.