An aerophone is a musical instrument that produces sound primarily by causing a body of air to vibrate, without the use of strings or membranes, and without the vibration of the instrument itself adding considerably to the sound.

An idiophone is any musical instrument that creates sound primarily by the vibration of the instrument itself, without the use of air flow, strings (chordophones), membranes (membranophones) or electricity (electrophones). It is the first of the four main divisions in the original Hornbostel–Sach system of musical instrument classification. The early classification of Victor-Charles Mahillon called this group of instruments autophones. The most common are struck idiophones, or concussion idiophones, which are made to vibrate by being struck, either directly with a stick or hand or indirectly, with scraping or shaking motions. Various types of bells fall into both categories. A common plucked idiophone is the Jew's harp.