Cymbals, often used in pairs, are commonly used percussion instruments that consist of thin, usually round metal alloy plates that are most often clapped together but are also sometimes struck with drum sticks or other objects. They are available in a variety of sizes and weights, with the larger ones being louder and sustaining their sound longer. Most produce an indefinite pitch, although small disc-shaped cymbals based on ancient designs, such as crotales, sound a definite pitch.
Cymbals were in widespread use more two millennia ago, including in ancient Greece, Egypt, Mesopotamia and India, and became common in classical music in the eighteenth century. They now also constitute an important part of popular music, and several types are usually incorporated into drum kits.