A sistrum (plural: sistra or Latin sistra; from the Greek σεῖστρον seistron of the same meaning; literally "that which is being shaken", from σείειν seiein, "to shake") is a musical instrument of the percussion family, chiefly associated with ancient Egypt. It consists of a handle and a U-shaped metal frame, made of brass or bronze and between 30 and 76 cm in width. When shaken the small rings or loops of thin metal on its movable crossbars produce a sound that can be from a soft clank to a loud jangling. Its name in the ancient Egyptian language was sekhem (sḫm) and sesheshet (sššt). Sekhem is the simpler, hoop-like sistrum, while sesheshet (an onomatopoeic word) is the naos-shaped one. The modern day West African disc rattle instrument is also called a sistrum.
The sistrum was a sacred instrument in ancient Egypt. Perhaps originating in the worship of Bastet, it was used in dances and religious ceremonies, particularly in the worship of the goddess Hathor, with the U-shape of the sistrum's handle and frame seen as resembling the face and horns of the cow goddess. It was also shaken to avert the flooding of the Nile and to frighten away Set. Isis in her role as mother and creator was depicted holding a pail symbolizing the flooding of the Nile, in one hand and a sistrum in the other. The goddess Bast too is often depicted holding a sistrum, symbolizing her role as a goddess of dance, joy, and festivity.
Researchers are not sure yet if the clay sistra were actual instruments that were used to provide music, or instead were models with only symbolic significance. But, experiments with a ceramic replica show that a satisfactory clacking sound is produced by such a design in clay, so a use in rituals is probably to be preferred.
The sistrum was occasionally revived in 19th century Western orchestral music, appearing most prominently in Act 1 of the opera Les Troyens (1856–1858) by the French composer Hector Berlioz. Nowadays, however, it is replaced by its close modern equivalent, the tambourine. The effect produced by the sistrum in music – when shaken in short, sharp, rhythmic pulses – is to arouse movement and activity. The rhythmical shaking of the sistrum, like the tambourine, is associated with religious or ecstatic events, whether shaken as a sacred rattle in the worship of Hathor of ancient Egypt, or, in the strident jangling of the tambourine in modern-day Evangelicalism, in Romani song and dance, on stage at a rock concert, or to heighten a large-scale orchestral tutti.
Various modern West African and Gabon rattle instruments are also called sistra (plural of sistrum): the calabash sistrum, the West Africa sistrum or disc rattle (n'goso m'bara) also called Wasamba or Wassahouba rattle. It typically consists of a V-shaped branch with some or many concave calabash discs attached, which can be decorated.