An allegory is a poem or passage in which characters, events, and images stand for something beyond their literal meaning, often a moral, political, or spiritual idea. The surface story can be read on its own, but it also points to a second layer of meaning that the poet wants readers to interpret.
For example, the various knights in The Faerie Queene by Edmund Spenser are allegorical representations of virtues such as truth, friendship and justice.
Example
The king of ash wore winter on his brow,
While three small candles guarded the door;
When one was named Mercy, the walls grew warm,
And the iron chains no longer clanged for war.
[n] an expressive style that uses fictional characters and events to describe some subject by suggestive resemblances; an extended metaphor
[n] a short moral story (often with animal characters)
[n] a visible symbol representing an abstract idea