percussion

noun

1. the hitting or impact of one body against another, as the hammer of a firearm against a cap
2. the shock, vibration, etc. resulting from this
3. the percussion instruments of an orchestra, band, etc. or the players of these
4. Med. the striking or tapping of the chest, back, etc. with the fingertips so as to determine from the sound produced the condition of internal organs

adjective

1. designating a musical instrument in which the tone or sound is produced when some part of it is struck, as a drum, or shaken, as a tambourine or a maraca
2. composed of or for percussion instruments: a percussion quartet