AGNUS DEI, in the church of Rome, a cake of wax stamped with the figure of a lamb supporting a cross. These being consecrated by the pope with great solemnity, and distributed among the people, are supposed to have great virtues; as, to preserve those who carry them worthily, and with faith, from all manner of accidents; to expel evil spirits, &c.—It is also a popular name for that part of the mass, where the priest strikes his breast thrice, and says the prayer beginning with the words Agnus Dei.