Usul

a rhythmic figure in Eastern music, performed on percussion instruments, usually drums and tambourines. The usul provides an accompaniment for singing, instrumental performance, and dancing and may range from relatively simple to quite complex. The term usul is used by the Tadzhiks, Uzbeks, and Turks, among all of whom the usul constitutes an element in the major vocal and instrumental forms. In Indian music, the corresponding term is tala. Among the Arabs and Persians, rhythmic figures of this type assume the names of various verse meters.