An idiophone is a solid instrument that vibrates when it is helllp

Struck

Explanation:

Idiophones are a category of musical instruments that create sound mainly by being struck. The sound is created by the vibrations that result from the instrument as a whole being struck, as opposed to the use of strings or membranes. Some of the instruments that would fall under this category are wood blocks, triangles, marimbas and some types of bells.