agnus dei

noun

1. Ecclesiastical.
   1. a figure of a lamb as emblematic of Christ.
   2. such a representation with the nimbus inscribed with the cross about its head, and supporting the banner of the cross.
2. a prayer addressed to Christ as Savior preceding the communion in the Mass.
3. a musical setting of this prayer.

noun Christianity

1. the figure of a lamb bearing a cross or banner, emblematic of Christ
2. a chant beginning with these words or a translation of them, forming part of the Roman Catholic Mass or sung as an anthem in the Anglican liturgy
3. a wax medallion stamped with a lamb as emblem of Christ and blessed by the pope

Latin, literally “lamb of God.”