emblem vs allegory

emblem and allegory both are nouns.

Word	Noun	Adjective	Verb	Adverb
emblem	Yes	No	No	No
allegory	Yes	No	No	No

As nouns, emblem and allegory are synonyms defined as:

emblem (noun)	allegory (noun)
special design or visual object representing a quality, type, group, etc.	a short moral story (often with animal characters)
a visible symbol representing an abstract idea	an expressive style that uses fictional characters and events to describe some subject by suggestive resemblances; an extended metaphor
	a visible symbol representing an abstract idea