percussion

1. The collision of two bodies in order to produce a sound. (countable)
2. The sound so produced. (countable)
3. The detonation of a percussion cap in a firearm. (countable)
4. The tapping of the body as an aid to medical diagnosis. (countable, uncountable)
5. The section of an orchestra or band containing percussion instruments; such instruments considered as a group; in bands, may be separate from drum kits. (countable, uncountable)
6. The repeated striking of an object to break or shape it, as in percussion drilling. (countable, uncountable)
7. The outer side of the hand. (countable, uncountable)

Plural percussions