allegory vs Agnus Dei

allegory and Agnus Dei both are nouns.

Word	Noun	Adjective	Verb	Adverb
allegory	Yes	No	No	No
Agnus Dei	Yes	No	No	No

As nouns, Agnus Dei is a hyponym of allegory; that is, Agnus Dei is a word with a more specific, narrower meaning than allegory:

allegory (noun)	Agnus Dei (noun)
a short moral story (often with animal characters)	figure of a lamb; emblematic of Christ
an expressive style that uses fictional characters and events to describe some subject by suggestive resemblances; an extended metaphor	a liturgical prayer beginning with these Latin words
a visible symbol representing an abstract idea