Kudüm is one of the most fundamental rhythm instruments in classical Turkish music. The person playing it is called kudümzen. It is among ney, rebap, and halile as one of the four main instruments in Mevlevi music. It consists of a pair of small, hemispherical drums. Traditionally kudüm was played in religious ceremonies; in a secular context, like in mehter music, its slightly bigger cousin nakkare is played.