Cistrum, a kind of ancient musical instrument used by the priests of Isis and Osiris. It is described by Spes as of an oval form, in manner of a racket, with three sticks traversing it breadthwise; which playing freely by the agitation of the whole instrument, yielded a kind of sound which to them seemed melodious. Mr Malcom takes the sistrum to be no better than a kind of rattle. Oiselius observes, that the sistrum is found represented on several medals, and on talismans.

Sisymbrium, Water-cresses, a genus of plants belonging to the class of tetradyomonia, and to the order of siliqueae; and in the natural system ranged under the 39th order, Siliqueae. See Botany Index.