The tambourine is a musical instrument in the percussion family consisting of a frame, often of wood or plastic, with pairs of small metal jingles, called "zils". Classically the term tambourine denotes an instrument with a drumhead, though some variants may not have a head at all. Tambourines are often used with regular percussion sets. They can be mounted, but position is largely down to preference. Tambourines come in many shapes with the most common being circular. It is found in many forms of music: Turkish folkmusic, Greek folk music, Italian folkmusic, classical music, Persianmusic, gospelmusic, pop music and rockmusic. Timbrel or tabret (the tof of the ancient Hebrews, the deff of Islam, the adufe of the Moors of Spain), the principal musical instrument of percussion of the Israelites, similar to the modern tambourine.