Source : Webster's Revised Unabridged Dictionary (1913)

Agnus Dei \Ag"nus De"i\ [L., lamb of God.] (R. C. Ch.)
   (a) A figure of a lamb bearing a cross or flag.
   (b) A cake of wax stamped with such a figure. It is made from
       the remains of the paschal candles and blessed by the
       Pope.
   (c) A triple prayer in the sacrifice of the Mass, beginning
       with the words ``Agnus Dei.''

Source : WordNet®

Agnus Dei
     n 1: figure of a lamb; emblematic of Christ [syn: {Paschal Lamb}]
     2: a liturgical prayer beginning with these Latin words