Percussion vessels consisting of a hollow object, usually of metal but in some cultures of hard clay, wood, or glass, which when struck emits a sound by the vibration of most of its mass; they are held in position at their vertex, the point farthest from their rim, and their zone of maximum vibration is towards the rim.

Source: Art & Architecture Thesaurus

http://vocab.getty.edu/page/aat/300041872