A type of image that transferred something that represents something else, such as Spring for youth, or darkness for death. Symbols are useful in transferring ideals carried in the image without stating them.
A symbol works two ways: It is something itself, and it also suggests something deeper. It is crucial to distinguish a symbol from a metaphor: Metaphors are comparisons between two seemingly dissimilar things; symbols associate two things, but their meaning is both literal and figurative.
Example
THE LONG HILL
Sara Teasdale
I must have passed the crest a while ago
And now I am going down--
Strange to have crossed the crest and not to know,
But the brambles were always catching the hem of my gown.
All the morning I thought how proud I should be
To stand there straight as a queen,
Wrapped in the wind and the sun with the world under me--
But the air was dull, there was little I could have seen.
It was nearly level along the beaten track
And the brambles caught in my gown--
But it's no use now to think of turning back,
The rest of the way will be only going down.
[n] something visible that by association or convention represents something else that is invisible; "the eagle is a symbol of the United States"
[n] an arbitrary sign (written or printed) that has acquired a conventional significance